1990 XJ headlight issue.

Been ages since I've been on here, hope someone can help me out with a nagging issue with my current XJ.

Ongoing problem for some time now; my headlights only work for 10-15minutes and then start cutting in and out. This is consistent and happens everytime I turn them on, they always come on no problem but after 10 minutes or so they start turning on and off at random. I'm not scared to tackle wiring issues but with 1 year old twins in the house
I just don't have a lot of time to dig into it. Also my desktop with all my wiring diagrams on it is currently not up and running. Factory fogs are also affected. ????? Anyone suggest any starting points? anyone able to help out with wiring diagrams?

Thanks a ton for any help anyone can offer.

I had the same issue with my '96. I think the problem is that the headlight switch heats up and a thermal overload kicks in. When it cools the headlights come back on, but it soon heats up again and off go the lights.

The factory wiring is undersized and now is 20 years old to boot. Connections have not gotten better with age. It is too much resistance.

Solution is to run relays for the headlights. Use the existing headlight wiring just to switch on the relays. Add a fused circuit or two from the battery to power the headlights via the relays.

I went with Daniel Stern Lighting, but I believe Putco is the brand of a popular plug and play harness. Search around using those key words and you will find a bunch of info.

Pull your headlight switch and check for melted / over heated connections there also.

As stated above, the proper fix on these rigs is to use the relay harness that takes the load off the factory wiring and puts it on the added relay / harness.