Headlight out ..puzzling problem
 

My 993 C4S left headlight is out. But strangely, first the replacement Xenon low beam failed, and after a couple of days, the stock high beam also failed. I checked the fuses, replaced the low beam bulb, cleaned and checked all the connections to the headlight unit. Checked the ground wire. One thing I noticed was that the wire that leads up to near the fuse box is connewcte3d to a small black relay or something (I don't what the function of that small box is ... could be the cause of the problem?). And that lead that bundles into the main wiring harness seems like it might be kinked a bit.
Anybody know if that little black box up near the fuse box could be the source of the problem?
Idea?

Not sure, but an A-B test of the input / output from the left side and the right side connections with a multimeter would isolate if they are different or the same. A photo of the little black box would help to identify if OEM or 3rd party.

That little black box is likely a headlight relay or part of a relay kit. If it’s failing or has a bad connection, it could definitely cause both beams to go out. I’d start by swapping relays side to side (if possible) or testing with a known good one. Also worth carefully checking that kinked section of harness for broken wires inside the insulation.