I have recently been driving more at night than I have in quite some time. While I do use my headlights in daylight quite often, this problem would not have shown in daytime. Over the last few night drives, after the headlights have been on for about 25 minutes, they begin to flicker. Not fully off and on, but enough to be easily visible. I tried turning the headlight switch off and on a few times, and flashing the high beams, but the problem is so intermittent and happens so seldom that it is difficult to tell the source of the problem using that method.
I finally worked on the problem this morning (hard to remember to do it- it's too dark and late to work on at night when I get home, and I don't see tem flicker during the day and so I forget). I first thought, "maybe a dirty fuse," but there are no fuses for the headlights. Next logical step 9and the easiest) was the headlight relay. Easily found without a shop manual by flashing the high beams on and off a few times. It is located right next to, and behind the battery on the inside of the fender well. I removed it and pried the case off by bending the little tabs back, and found that the contacts were arced more than I would like and had a bit of carbon on them. After cleaning the contacts up I also cleaned the spade connectors on the base of the relay and applied a bit of silicone dielectric grease. haven't driven it for any length of time yet, but from the looks of things, that was the solution.
On a side note, the workings inside the relay are a thing to behold! __ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"