Intermittent HID headlight failure - troubleshooting?

I got a 2nd hand 2011 Ford Fusion this year, to which the previous owner had added (aftermarket?) HID headlamps. Last week I’d noticed on the 10 minute drive home that the headlamps cut out… only to cut back in a minute or two later. On an 8 hour drive this weekend, they cut out about 6 hours in, then worked the rest of the trip after a 10 minute rest.

Is there anything about this I can possibly fix myself? Is it indicative of a part about to fail? If it is failing, are parts interchangeable, or do I need to find a 5 year old out-of-production phase inverter from Guangzhou Durable Lighting Industries?

Driving the Rockies in pitch darkness was briefly exciting, but that must be what fog lamps and high-beams are for

Without knowing exactly what system is installed and how the previous owner installed it, there is no factual answer to this question.

If it was my car I’d be restoring it to factory configuration ASAP.

put halogens back in and throw that dollar store HID junk in the garbage.

people who buy and use those things piss me off.

I’ve often given help for computer advice with similar amounts of input - I think someone can help.

No thanks.

Thanks for the advice. :dubious:

Check all your connections for looseness / corrosion.

Seconded. 99 times out of a hundred, an intermittent electrical problem can be traced to a poor connection somewhere being broken and made by random factors like vibration, temperature/humidity variations or the phase of the moon.

Start at each headlight in turn, pull gently on the wiring to test if it’s secure, or just being held in place by force of habit. Disconnect all the connectors, see if any of them feel loose or look corroded. Anything besides clean metal visible on the connecting parts could cause your problem, and should be cleaned. Depending on how easy the metal parts are to access, this might be doable with sandpaper, some other abrasive or contact cleaner.
For some particularly awkward/badly corroded connections, it may be simpler to replace the connector with a soldered joint, or a new connector (this may not be a good idea if the fault lies in your car’s original wiring, but I’d wager it’s somewhere around wherever they connected the new headlights into the car’s loom, with my second chance bet going on a poor grounding to the car body, just based on past experience of troubleshooting DIY car mods usually taking much longer than it would have to fit the offending item properly).