I picked up an E82 135i on Monday. As the title suggests I've got an issue with the HIDs, specifically the passenger one.

When I turn the headlights on it will start every single time then it will randomly switch between being off and on with no rhyme or reason. It will turn on for a random period of time, then off for a random period of time, then on for a random period of time, etc with no predictability. I've had it turn off then back on a few times then stay on for a few hours, I've had it stay running the whole time, I've had it shut off a few seconds after turning on the lights and stay off until I manually cycle the lights at which point it just goes back to working randomly. The only repeatability I can influence is totally shutting off my headlights or turning on the passenger headlight once before it goes into it's own little lala land. If I shut the headlights off when it's shut itself off it will turn itself back on then they'll shut off.

It is not affected by vibration which was my original assumption. Sitting parked it can cycle between on and off, where it might not even shut off a single time going down a road composed entirely of potholes.

I'm going to swap headlight bulbs between sides then ballasts, but is there anything else I should try before going to a new footwell module?