A 30ma bulb at 16 volts is near a half watt of power. About as hot as those resistors are probably getting. They way to get non-melting bulbs is to use a LOWER voltage bulb, the lowest current 1.5V bulbs you can find, and a bigger (value, not physical size) resistor. But this is not EXACTLY the same as repalcing the bulb with an LED and resistor, except the LED will never even get slightly warm.
As was stated, you can buy decoders that will replace the board in the looco and allow you to connect LEDs or 1.5 volt bulbs directly, the same way you wouuld put incandescent bulbs in a DC loco - no extras, the decoder already has the required current and/or voltage limiting in place, just hook up the red and black track pickups, the orange and grey motor (and if your loco is supposed to run long hjood forward, just reversing the orange and grey wwill make forward be the long hoood end - I do this with all my P2k Geeps for the same reason, they are factory set to run short hood forward but my railroad ran them long hood forward. They even come factory painted with the F on the long hood end like it's supposed to be).
Either type will work. There is no difference to installing LEDs to an LED supporting decoder than connecting incandescent bulbs to one designed for 1.5V bulbs. The wiring is the same.
This version of P2K loco is a real pain to use the factory board - that's why when I did it I just remved the whole mess adn soldered the respective wires in place. If all else fails, there are amny reputable vendors that do the installation for you, but when it comes to hard wiring the decoder in, these are really some of the easiest because they have wires to all the connection points already and it is easy to figure out what is a track pickup vs what is a motor wire. It's the ones where the frame serves as part of the circuit that get more difficult to wire in a decoder.
There are countless videos showing decooder installs - they do not have to be for the exact loco, the concept is exactly the same regardless of who makes the loco. Yoou have 2 wires from each truck for the power input, 2 wires to the motor, 2 wires to the front light, and 2 wires to the rear light. The order of the wires is exactly the same no matter if it's a P2K loco, an Athearn, or an Atlas. It's a fairly large loco so there is plenty of room to work, The same basic supplies will work for every install - some small diameter heat shrink, some Kapton tape, small diameter solder, and a low power soldering iron (25 watts is plenty).
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
A followup to my earlier posts:
I gave up (at least for now) trying to get the headlights to work on the Proto 2000 SD9 that was the subject of this thread.
Current status -- looks good, runs very well (using Soundtrax Soundtrax MC2H104 OP), considering that this unit had been sitting "new in the box" for many years.
I cut the "cut here for dcc" wire on the board, but after doing so, I could never get the orange wire end to work in any setting that I tried. The only headlight that will illuminate is the F end (which is really the R end on a long-hood-forward engine like the SD9).
But in any case -- I noticed that the factory lighting/circuit board has two large grey resistors that get very hot to the touch when the headlight is used. Since I've read reports of the heat actually melting body shells, I'm not using the headlight at all right now.
I'm still open to getting working headlights "some other way".
First off, a quote from an old Clint Eastwood movie:
"A man's got to know his limitations".
And... I know mine. My vision isn't good, my dexterity isn't so good, either. Nor do I have a broad array of tools, and I don't have a decent workspace in which to use them (if I had them).
So... any fix is going to have to be an easy one.
I'm not interested in LEDs. Any fix will have to be with incandescent bulbs.
I won't be using 3v or 1.5v bulbs. Any fix will have to be with bulbs that run at track voltage (16v). But I don't want bulbs that run too hot.
So I need some knowledge first.
I see the following bulbs available from Circuitron:
800-7440 General Purpose, Long Life Miniature Lamp. 3.0 mm Diameter with Black 12" wire leads. 14 - 16 volts, 30 ma.
This satisfies my criteria for a bulb that runs at track/decoder output voltage. My next question is current consumption insofar as it relates to heat.
A bulb with a lower milliamp rating will run cooler than one with a higher rating, is this correct? I don't mind if they "run warm" (of course) -- just not "too hot".
The 30ma bulbs are about the lowest milliamp rating I can find for 14-16v. My guess is that this will yield a long life, and I DON'T CARE whether they're overly bright or not. All I want is some kind of lighting, even if only "marginally bright".
So... I think these bulbs will do the job.
Comments...?
I got some time to try out my solution to the Rule 17 problem mentioned herein. I have posted it as a new topic.
Ed
There is no reason to fear LED's. You can buy 3mm warm white leds on ebay from China for 8 cents a piece or a seller in the US for 10 cents. 1K ohm 1/4 watt resistor for 3 or 4 cents each.
Get one of those helping hands,
https://www.ebay.com/itm/Helping-Hand-Magnifier-Glass-and-2-alligator-Clamps-Jewelry-Watch-Repair-Tool/271160862878?epid=710144903&hash=item3f2272689e
and start soldering. After you do 10 you will feel like an expert.
Henry
COB Potomac & Northern
Shenandoah Valley
I would instead get a decoder that can handle LEDs with no external components and use LEDs, before I would use 16v incandescent bulbs. Those WILL get rather warm. Plus you'll never have to go inside the loco again, the LEDs will never burn out.
From reading the replies just above, I'm thinking of:
- buying a full replacement circuit board that DOES NOT have a 1.5v output, and then...
- buying new (incandescent) bulbs to replace the 3v bulbs in the loco. They use stranded wire and should be very easy to replace.
I see I can buy a "bundle" of 10 or so replacement bulbs, for about $10 or so, and I'll order them when I order the replacement board.
But... what voltage should I buy?
I see I can get either 12v or 16v bulbs. I'm using a Roco z21 and the track voltage is set at 16v. So... is that the proper voltage to get?
OldEngineman 7j43k wrote: "Some replacement boards just clip on the mounts for the old ones. I've got two Genesis GP9's that I can do that with (TCS A6X)." With the A6x, did you retain the 1.5v incandescent bulbs? Is anything out-of-the-ordinary required to get 1.5v output on the light tabs instead of "full voltage"? I tried to find documentation on how to use this feature at the TCS website but couldn't locate any...
7j43k wrote: "Some replacement boards just clip on the mounts for the old ones. I've got two Genesis GP9's that I can do that with (TCS A6X)."
With the A6x, did you retain the 1.5v incandescent bulbs?
Is anything out-of-the-ordinary required to get 1.5v output on the light tabs instead of "full voltage"?
I tried to find documentation on how to use this feature at the TCS website but couldn't locate any...
I intend to keep the 1.5V bulbs. I haven't done the installation yet--been busy. I DID see on the documentation that the 1.5V supplies have different tabs than the others. There's 3 ways of connecting things up: 1.5V incandescent, "12V" incandescent, and LED.
I found clear wiring instructions on the Decoder Literature.
And programming in their Programming guide. Including dimming. That's constant dimming, I think, which means you can't change it with a button push. BUT. I noted earlier the idea of have two sources for each location. And, since this decoder is 6 function, that means you can have close to real headlight operation. I think. Now that this subject has come up, I'll likely do this to those two GP9's sitting over on the table.
I do think getting the wires soldered onto the little bitty tabs (some are little, anyway) might be the worst part. I've had years of practice, and I've got a great soldering station. So what's easy for me might not be easy for others.
But when yer playing with little bitty trains, things tend to get little. And bitty.
PS: You MIGHT be able to dim the 12V supply down to 3V, or so. If you start with the lowest dimming CV value, and work up, you likely won't blow a bulb. I hope.
Yes, there are resistors built on tot he board to drive the 1.5V bulbs. Other decooders are built to drive LEDs with no extra resistors, those often have a current source that only provides a limited current to the LED - LEDs don;t really care about voltage, just the current.
The problem is, many P2K locos use 3 volt bulbs, not 1.5V like Athearn. You won't blow them up using 1.5V, but they may not be bright enough. You might have to swap them out for 1.5V bulbs to use one of those decoders.
OldEngineman Installation with these looks like it's just a matter of unhooking the wires, removing the old board, putting the new one in place after re-attaching the wires.
Installation with these looks like it's just a matter of unhooking the wires, removing the old board, putting the new one in place after re-attaching the wires.
Some replacement boards just clip on the mounts for the old ones. I've got two Genesis GP9's that I can do that with (TCS A6X). And I did it with an Atlas GP7 (Loksound Direct).
Other boards may not use the same mounting style. I've got some Athearn SD40-2's where I will be using the TCS A6X (1.5V bulbs, etc). I don't think they'll be an easy clip on.
rrinker As for Rule 17, I'm pretty sure most of the decoder manufacturers understand what it is. They also undertand that most users don;t wnat to be whacking buttons all day as they run their locos to make the lights do the right thing.
As for Rule 17, I'm pretty sure most of the decoder manufacturers understand what it is. They also undertand that most users don;t wnat to be whacking buttons all day as they run their locos to make the lights do the right thing.
Over on the Atlas Rescue Forum, there's talk about all the DCC functions you can have in a caboose:
Two kinds of whistles
Handbrake
Coupler clank
Slack running out
Whole lotta "whacking" there. All day.
The only whacking necessary for the locomotive lighting is to dim while stopped for oncoming trains.
Another approach?
I've just stumbled onto a different solution that might work.
It seems there are several replacement circuit boards available. Instead of plugging in a decoder, these replace the entire analog light/circuit board with a new dcc board.
Here are some examples:
https://tonystrains.com/product/train-control-systems-a4x/
http://www.hiawathahobbies.com/MC2H104AT-DCC-Control-Only-Decoder--Atlas-Others-Board-Replacement_p_31348.html
https://www.traintekllc.com/tcs-train-control-systems-1000-a4x-ho-scale-decoder/
https://www.traintekllc.com/tcs-train-control-systems-1001-a6x-ho-scale-decoder/
(the last one specifically states that it even works with older 1.5v bulbs)
Installation with these looks like it's just a matter of unhooking the wires, removing the old board, putting the new one in place after re-attaching the wires. It may be necessary to put some insulation under the replacement board and tape it down, because there don't seem to be any screw mounting holes that match up.
For me, I'd much rather try this than any "re-wiring".
I'll save the surplus decoders I already have for future installations in "more modern" equipment.
I assume you bought this loco used? because that black wire you cut is not stock. The "cut here for DCC" marks a trace on the circuit board that should be cut. It's almost like someone sliced through the trace, then changed their mind, or converted it back to DC, and ran a wire across the cut area. The end that is closest to where the decoder plugs in (I downloaded the picture and flipped it over so the front is to the right - so I could read the markings easier) looks a bit chewed up - you do need to be a little careful soldering to PC boards or you can ruin the traces. That board is similar but not identical to mine. It's hard to follow all of it since there are traces on the bottom side as well.
It appears RL2 comes over to one of those diodes (black things with single band), then goes over to the terminal of a second diode (diagonal trace under the 4 diodes). This then leads to a trace that goes diagonally under the resistor (the greey things are resistors) and over to the decoder plug - presumably to the yellow wire, since it's closest to that. The front light is probbaly reversed, since FL2 got to a diode terminal and ALSO to the horizontal resistor, which then goes over to the vertical resistor and then - who knows, the trace is on the bottom. Guess we need a shot of the other side as well. And if the decoder plugs in - unplug it, as there are traces hidden under the plug.
It's just enough different from my older one that the traces are not all in the same palce. I know witht he one I had, I traced out the circuit diagram and discovered that once you cut the "cut here for DCC" traces, only 1 of the two resistors was still in the circuit. The whole thing made no sense, which was why I ripped it out.
Do we know the bulb for the rear headlight hasn't burned out?
Here's the circuit board:
(sorry the pic won't post, I'm using microsoft onedrive for storage and even though it provides a link for pasting into message boards, it won't paste into THIS one. You can view the image or download it from the URL below).
https://1drv.ms/u/s!An3uN8X2AHdOgm5EZSGzx9fr0aTr
F headlight is on left (white wire)
Connectors seem to be (on your left)
RR - right side power (f truck)
FL2 - front light
FL1 - front light
LP - left side power (f truck)
Connectors (on your right)
RP - right side power (r truck)
RL2 - rear light
RL1 - rear light (light is removed right now)
LP - left side power (r truck)
There are two additional connectors to the motor obscured by the dcc wires.
The wire that I cut is the black one just above the horizontal resistor.
I noticed that the large grey resistors (is that what they are, or are they something else?) seem to be connected to the "FL2" and "RL2" connectors (I think).
Are these the "common" (i.e. blue) wire?
I'm thinking: green wire --> bulb --> wire to common. But which one?
Could I run it to FL2? I'm assuming the common is "live all the time", so it wouldn't matter if the front light was on or off. Where does the resistor go?
What size/type of resistor? I have next-to-no "pre-knowledge" about working with such components, so you've got to be specific and speak like you're talking to a 10-year-old.
I'm considering just soldering the cut ends of the black wire back together, and running it with both headlights on, and be happy that way...
OldEnginemanRegarding "brightness of the bulbs", I'm completely satisfied with the way the incandescent bulbs are working.
Many of my early Proto 2000 DCC conversions I left the stock lamps in place or even replaced them with other 14 or 16 volt GOW lamps. I learned the hard way that the built-up heat had distorted, and even destroyed some of my plastic shells.
The designers never figured the heat of those lamps would ever amount to much since, in DC the locomotive didn't operate at full throttle all the time.
In DCC the lamp burns constantly at near full brilliance. The heat builds up quickly. I've ruined two Genesis F units, a couple Proto 1000 RS-2s and the worse was a Life-Like Berkshire that completely melted the headlight off the front of the smokebox.
At the time I did my conversions, white and "yellow-glo" LEDs had not been available. There was a bluish-white 5mm available but not very useful as a headlight.
Loksound decoders, maybe others, have an option to "ramp-up" the LED brightness to simulate an incandescent lamp. It is pretty convincing.
Good Luck, Ed
Can you post a photo of the board? Or several, if needed, so show th ewhole board from front to rear?
Your best bet is to follow the connections from the rear bulb. One should go to the blue wire, this is the common for all functions. The front light should also connect to the blue wire. The other terminal of the rear light should lead up to the point where you cut, since before you made the cut, it got power, and now it does not, and that's the only thing that has changed. There may be other components int he path - in fact there pretty much HAS to be a resistor. For the purposes of following where the power is supposed to go, treat the component as a wire, like the power just goes straight through. It does not matter for this purpose precisely what that component does. The side of the cut that links to the rear bulb is what should get connected to the yellow wire. You can use the green or violet wire, those are just additional function wires, it will just mean a slight change of the CVs to make the proper wire turn on - the way you have it now, the button for the rear light turns on the yellow wire, you will want it to turn on the green wire instead. The dimming may or may not be able to function on functions other than the yellow and white.
Randy wrote: "in this case it is the factory circuit board thwarting you. The fact that the rear light now does not come on at all means it was getting power front he headlight, that path is no longer there with he trace cut, but the yellow wire has to be in the right place."
Your points are all well-taken. Thanks for sticking with me so far.
I've come to the conclusion that even though the white wire (F end) works as it should, there's no way I will get the yellow wire to work with the factory circuit board. The version of the Proto 2000 SD9 that I have doesn't have "traces" on the board to slice through with a knife -- instead, it has a black wire with "cut here" printed nearby on the board. No "x's" to be seen.
Before I cut the wire, both lights would illuminate when the R end headlight was activated. After cutting it, nothing. (again F end white wire continues to work correctly)
I tried taking the circuit board off, to look underneath, and consider myself lucky for being able to get it back on. Can't see, and the hands don't work well enough any more for such small components!
I'm wondering if there could be an alternative way to accomplish this -- to do some partial "re-wiring" for the R end light only, without replacing the entire board?
I see the decoder has the green wire "hanging free".
Would it be possible to connect the R end bulb to the green wire, with the other lead (from the bulb) running to a "common" on the board? Perhaps to the common on the F end (white wire)? With a resistor if I need one? Or to another common? (that's the blue wire, correct?)
Then perhaps I could use the green wire function as a simple "on/off" switch to apply power to the R end bulb.
Is this approach possible?
If so, perhaps we can discuss it further.
Regarding "brightness of the bulbs", I'm completely satisfied with the way the incandescent bulbs are working. Bulbs are fine (not overly bright) on full and good on dim. No complaints and I'd prefer to keep both of them as they are...
There is no such thing, really, as DCC Ready. There are locos labeled as DCC Ready that have wiring bad enough that the decoder can be eaisly fried if you simply plug it in. Then there are some that it really is that simple, just plug it in and go. And everything in between. You have one of those "in betweens" It mostly works.
If the yellow wire from the decoder is in the hole marked for the yellow wire, there ought to be a path from it to the light bulb. Also, if I recall from wiring one of those, there are more places you are supposed to cut for DCC, not just that one. In my picture of installing it from 13 years ago, I only have one shot that shows the factory board and it's not exactly a closeup so I can't see all the details.
Somethign to keep in mind, most P2K locos use 3V light bulbs, dropped across some diodes for the constant lighting on DC. In the case of the SD, it's those two big resistors that drop the power - and get rather warm. DCC decoders, unless you get ones already set up for LEDs, put out 12-14 volts on the function wires. That will make the headlight a flashbulb. Athearn, until their very recent announcement, has been using 1.5V bulbs in their locos - an even brighter and more brief flash when 12-14V is applied. Plus, those low voltage incandescent bulbs were fine for DC, where you typically run at the lower end of the speed range, with reduced voltage. At least, since you are interested in prototypical light operation, I doubt you run your trains around at full throttle like slot cars. So the bulb is getting less than full power. With DCC, when the headlight is on, it gets full power, all the time (unless dimmed). This can lead to the bulb getting warm enough to soften the plastic - yet another reason I switch all mine to LEDs.
As for Rule 17, I'm pretty sure most of the decoder manufacturers understand what it is. They also undertand that most users don;t wnat to be whacking buttons all day as they run their locos to make the lights do the right thing. Just like automatic directional lighting when that started getting added to DC locos. No, real locos don't automatically change which light is lit when you change the reverser handle. Those that know how it really works are quick to complain how the default Rule 17 action isn't prototypical, but you have to face it, those that know how it really works are a minority. And also, in the early days of DCC, you only had 4 functions in the protocol specifications, and most decoders only had the headlights, no extra wires for beacons or lights (and even then cost $60 or more). This actually is one of the reasons why, back in the early talking days for defining a command control standard, I was is favor of CVP's Railcommand - it had independent buttons on the controller for the front and rear lights! That's because it was developed by and with the support of some serious protypical operators. Not that Bernd Lenz and his crew were unfamiliar with prototypical operation - but what they were familiar with was European operation. The history of the design of DCC does play a part in how things work today, and most do allow you to change from the default automatic stuff to manual control - in this case it is the factory circuit board thwarting you. The fact that the rear light now does not come on at all means it was getting power fromt he headlight, that path is nolonger there witht he trace cut, but the yellow wire has to be in the right palce. I think there is a pad labeled for it, it does not pull from the 8 pin socket one that trace is cut. A limitation that results from them trying to make it fully functional in DC PLUS allow installing a DCC decoder without having to replace the low voltage lamps used.
gregc wrote: "it seems to me that on the TCS T1, setting CV61 to 49 will automatically support rule 17."
But... I DON'T WANT "rule 17".
I want an F end headlight that is independently-controllable from the r-end headlight. (off/dim/bright)
I want an R end headlight that is independently-controllable from the f-end headlight. (off/dim/bright)
The "rule 17" feature on decoders (and on dc only locos) does not support this.
My experience is limited, but I have the headlights set up on two other dcc engines that I have up and running so far.
One is a Walthers Proto SD9 that came with ddc and sound pre-installed.
The other is an Atlas Trainman RS32 that I installed a basic Digitrax decoder into.
There must be something on the (older) Proto 2000 circuit board that prevents this, however.
I guess that "dcc ready" isn't really "ready" all the time...
Aside:
Many folks don't understand how rule 17 works "on the big engines". Nor do the people who make these decoders.
I don't want to get into a discussion about how to control the headlight on the engine one is running. I recall serious grudges (not by me, but held by others) because one guy forgot to dim the headlight for some other guy. I forgot myself now and then, things like that would "just happen" because you were busy with something else at the moment. In cases like that, "sorry" on the radio would be enough, and then you went on and forgot about it...
it seems to me that on the TCS T1, setting CV61 to 49 will automatically support rule 17.
this built in feature is probably the thing getting it the way of manually controlling the dimness of both lamps
greg - Philadelphia & Reading / Reading
I went ahead and cut the wire (only one that said it should be cut).
The white wire illuminates and dims. It's light isn't overly bright, either. I don't see why there are warnings that it will burn out, it's nowhere near that bright.
But now the yellow wire end stays dark, regardless of what I try.
I don't really consider myself as having the eyesight nor the manual dexterity nor the competence to tear out the existing board and start re-wiring myself. So I'll let that pass, rather than risk having an engine that won't run at all.
I think I'll end up using the loco with a working headlight on one end only. Guess I'll learn to live with that.
It just seems odd that the white wire works, but nothing I try sends power to the yellow wire (independently of the white wire).
Oh, well...
And, if you replace the board and DON'T go with sound, you can add more weight in the bigger space.
I've got a couple of non-sound Genesis GP9's, and I'm going to replace the board with TCS A6X's. And add some nice toxic lead.
I mentioned that many posts ago - those "cut here for DCC" P2K boards are best just removed completely. I'm in fact surprised if you haven't cut at the marked locations and the decoder hasn't fried - part of the wires you need to cut connect the track pickups (red and black) to the motor (orange and grey).
The configuration offered by TCS would have done the exact same thing you have with the Soundtraxx decoder. One button would turn the white wire ona dn off, another button would turn the yellow wire on and off, and F4 would dim whichever one you had on (or both if both were turned on). Both of them coming on with one button is the same problem - those ^#$( factory circuit boards. There are very few locos I ever leave the factory board in place (even more important with sound where the more space for a larger speaker, the better).
At least start with cutting the board where it says to cut. Make sure the trace is truly cut through - use a meter (remove the decoder first! Even the low voltage used for the ohm test in a multimeter can damage the decoder is applied to the output side). Touching the probes to the bare trace on either side of the X before you cut it should show 0 resistence, or beep the meter if it has a beep continuity mode. After cutting through at the X, it should be infinite resistence, or no beep.
But I still say - ditch the whole thing. On the TCS T1 decoder, there is a 9 pin connector at the decoder, and wires. Red wire goes to teh right side rail pickup, black goes to the left side pickup, oragane to the motor + (whichever side was connected to the rail on the engineer's side when the loco was facing forward - the forward you want it to be, or as marked - P2K didn;t follow all protoypes and tended to make the locos all the same way regardless of how the railroad they were decoreated for actually ran them, I'm always flipping my GP7's around), grey goes to teh other motor terminal. White to the front headlight (if you keep the incandescent bulbs you need a resistor, or replace with LEDs and resistors), yellow to the rear light (white and yellow are the negative side if using LEDs), blue to both lights (positive for LEDs).
It's time for a followup on my problems getting the headlights working independently on an older Proto 2000 SD9.
I received a Soundtraxx MC2H104OP decoder and that's now installed onto the loco chassis.
Using Decoder Pro I was able to tinker with the function and light panels and I now have the F light (white wire?) on/off set to Button 5 and the R light (yellow wire) set to button 6. I also set button 4 to be a dimmer.
The white wire illuminates in both directions with button 5. (ok)
Pressing button 4 dims the white wire. (ok)
BUT...
When I activate button 6 (yellow wire), BOTH lights still illuminate. (NOT ok)
Pressing button 4 dims both. (ok)
I'm feelin' like Charlie Brown .... Arggghhhh!
I'm beginning to think that this problem could be due to something "hard wired on the circuit board", instead of within the decoder.
I've looked over the instructions/info that came with the unit. There's a section on dcc, and part of it reads:
"By installing a suitable decoder in the digital ready socket, even the locomotive's headlight can be independently controlled".
Well, ok.
'Cause that don't work, having tried TWO decoders already.
Neither produced the desired results.
BUT... hang on a minute.
On the circuit board, there's a small black wire (kind of like a loop), and the writing "cut for dcc". I'm wondering if this could be some kind of "connection" between the white and yellow wires intended for operation in dc mode.
So... I'm reaching out to those who have worked with these older Proto 2000 circuit boards (I believe this engine was one of the first-generation production models, as it came with NMRA couplers).
What is the small black wire for?
Why does it say to cut it?
What results will happen if I cut it?
I DON'T wan't to cut it and have the loco not run anymore, because other than the headlight, it runs just fine.
Thanks!
wjstix I'll have to check, but I'm pretty sure one brand of decoders (maybe MRC?) have a setting where the lights will toggle off-on-dim-off each time you hit the F button controlling lights...but not sure if it's for only both lights, or if it can be set to do each separately?
I'll have to check, but I'm pretty sure one brand of decoders (maybe MRC?) have a setting where the lights will toggle off-on-dim-off each time you hit the F button controlling lights...but not sure if it's for only both lights, or if it can be set to do each separately?
NCE 4 function decoders have the desired control - there is a function map that dims with F4, and another that dims with the F8 button - so you set wire up to use the dim with F4 and hook that to the front light, and another outoput to dim with F8 and hook that to the rear light. So now you have 2 buttons for each light, one turns it on and off, the other toggles dim/bright.
That's another possibility, TCS uses CV64 for the dimming brightness, and the default is 15, which is suitable for incandescent bulbs but not LEDs. If using LEDs, try CV64 = 3 or 4.