HID Headlight Fix

My repair shop specializes in hybrids. As an offshoot of that, we became dealers for used cars, primarily Priuses. Pretty soon it became obvious to us that there is a chronic problem with intermittent HID headlamps and a lot of advice about using the correct bulbs,etc. I decided to tackle one of our cars that had been out for overnight test drives only to have customers tell us they couldn't drive at night because the lights wouldn't stay on. I decided to let the car sit in the lot with the lights on and sure enough, after about five minutes one headlight would go out, then the other. Replacing the bulbs with the correct high quality units did no good, so I found new power supplies on eBay and gave them a shot. Same thing. On a whim, I took the old power supplies and bulbs and set them on the bench and applied twelve volts to them using clipleads and a battery jumper box. They ran for hours until they killed the jumper box I was using to power them. It was then time to bust out the voltmeter and do some real diagnosis. Long story short, I found the problem is the red-black wire pair inside the headlight that provides twelve volts to the headlight power supply. Over time, the crimps become high resistance and act like a thermal switch. You can take the plugs apart and solder the crimps and, voila, the headlights now burn ad infinitum. View attachment 82648 View attachment 82648 View attachment 82649 View attachment 82650 View attachment 82650 View attachment 82650 View attachment 82650 View attachment 82648 View attachment 82649 View attachment 82650 View attachment 82650

 

I have to back off of my original post a bit. On the vehicle in question, this approach did seem to resolve the issue when all else had failed. The vehicle is still out there in service and the problem has not come back, but since then, we have resolved the problem on numerous other cars by simply installing high quality Sylvania bulbs, so I'm not going to advocate the soldering approach on a regular basis.