When I turn on my high beam lights, they work when the turn indicator/high beam switch is pulled back, but when I release it my head lights go out. My regular lights work fine. Also, are there any in cab "courtesy lights" in the '91? It sure is dark at night when I get into it and try to find the ignition.
High Beams don't work! on 1991 Jeep Wrangler
I think you need to check out your high beam switch to see if it's failed. The 20 amp fuse #5 controls three courtesy lights in the Wrangler according to my wiring diagram. Try to locate the courtesy lights and check the fuse. If you need some help, go to an auto electric shop or a Jeep specialist, here's a directory link for you: