May 20

One light (L/R) won’t always fire

So I did a retrofit to my wife's Ford Edge a couple years ago, using the TRS mini D2S 3.0 universal kit. Everything worked great for the first year and a half or so. Been having an issue where, upon starting the car up, only one headlight will fire up. Thought it was a bulb at first because it was always the passenger side, so I put two new bulbs in. That seemed to do the trick, but shortly after, started having the same issue, but it wasn't always the passenger side. Now, more often than not, only one light will fire, and it's anyone's guess as to which one it'll be at any given time. Oddly enough, they never both, not fire (thankfully).

Flipping them off and then on will sometimes make the other bulb fire, but not always. I talked to TRS and they suggest to troubleshoot by swapping ballasts, side to side, and then ignitor, side to side, until I can isolate the issue. Have tried this several times, but wind up having the same problem of one light not firing, and not ALWAYS the driver or passenger side.

I'm no electrical wiz, but hoping someone with experience in troubleshooting this type of issue, might chime in. My next course of action with TRS is to mail them everything and let them find the culprit, and mail me back my working parts and a replacement (under warranty) for whatever the problem part is. I'd like to avoid this as it means removing the bumper to take the headlights out and go back to the factory ones, which I'd like to avoid if possible.

Any ideas on what I can try to nail down whatever is causing the randomness of one light firing?