Which pins do you connect to the capacitor and which pins connect to the lights, or are you using LEDs? I already have installed 12 volt lights in the flashers. Can I use them or do I need to redo with LEDs or 1.5 volt lights?
I use the LM3909 in the 8 pin DIP package. The pins are as follows: 1, jumpered together with #8 also connected to negative side of capacitor, 2 positive side of capacitor, 3 not used, 4 negative side of power supply, 5 positive side of power supply, 6 anode of LED, 7 not used, 8 cathode side of LED and jumpered to #1.
I've only ever used these with LED's and have used a single cell battery to power the circuit. The power draw on the battery is so small that the shelf life of the battery is more an issue as to how long it lasts.
LM3909 circuit
The diagram is for an LED circuit. You can use 1.5 or 3 volt bulbs as well.
Not sure if 12 volt is too high or not. The National Datasheet for the LM3909 shows a 6 volt lamp flasher circuit.
Just google LM3909.pdf