[hdinch]

Installed LED headlights in my 73 bird, seem to work fine in the garage and was done with it. Went to do some other work a few weeks later and no headlights. I switched out the dimmer switch and the lights did a flicker then never came on again. I have power to the dimmer switch and the headlight wires. I also see the dimmer switch has power to the prongs when I click the switch. So that might leave the headlight switch...I don't have one at the moment but is there anything else this could be? Still wondering why the LED lights caused this. I put the old lights back in to check that...nothing.

[Bill Hanlon]

If power is good at the dimmer switch, the headlight switch is OK.

[hdinch]

So any idea of what to look at? This seems odd then since I am getting power with my test light from the lights and switch wires.

[Sirrotica]

FWIW, My wife's car is a 2008 Vibe which has daylight running lights incorporated into the, but no resistor to stepdown the voltage for daylight running, so it tends to burn the OEM style halogen lights out frequently. If I get 6 months out of a pair of OEM style bulbs I'm lucky, BTW, they are a PITA to change because of all the obstructions behind the sockets.

I tried a set of the LED conversions, and they lasted about 2 months before 1 of them quit working. It just burned out, I don't think the aftermarket has the LED conversions worked out very well yet. They seem to draw a lot of amperage between the light, and the little cooling fan used to cool the unit. At least that's how the conversion I had was constructed.

Just a suggestion, as the LEDs seem to draw a lot of amperage, you could have exceeded the amperage carrying ability of the old wiring and bulkhead connectors and burned something up between the inside of the car and the headlight sockets at the front of the car. The old wiring and connections have a lot of resistance when they're over 45 years old. Try a test light at the end of the wiring and keep working back towards the switches inside to find your problem.

If you have juice at the end of the harnesses, the other problem would be a broken, or bad ground wire out front in the core support area. Hopefully this may help you track down the problem.

If your wiring has burned up between the switch and the lights due to too much draw, a headlight relay would be the best step to keep the LED setup working without taxing the OEM circuit beyond it's design limits.

[steve v]

If you have power at the headlight plug ends check the ground wire. If the ground is good you may have an issue with the new bulbs.
Did you try plugging in the old bulbs just as a test?

[hdinch]

So to further confuse the issue...I went back out to go over things again and saw both switches were giving power and just left the original dimmer in, looked at the ground on the core support and it was solid. I put that there a few years ago and it's good. I have wiring going from one headlight to the other side plugging in the original wiring, the 3 prong connectors were always a little loose to the headlights. This setup is made to give a tighter fit. No issues there and there have never been. After checking that and had the original headlights back in...the lights work. Now I had put them back in before I came back out and put that in my first post. Not sure what happened and not much changed. I did not put the LED's back in...However, it sure seems that they are the issue as that is what caused the original problem. My alternator is putting out 14 at the gauge.

[hdinch]

Replying to my last update...original lights will come one then hit the dimmer on and off then they got back to failing. Now they do not come on..very odd now that I went back to the original lights. Internal lights and running lights are fine. I tried another dimmer switch no change.