I posted this in "ask the techs", no much response. Help appreciated

Headlights would not come on with startup last night. After a few minutes, the came on. Went a few miles on a dirt road and the flickered on and off, then stayed on. I have had JK's harness for three years with no problems. Park lights stay on. Checked the grounds and looked at the harness today and everything looks good. lights didn't work on auto or with the switch. Put everything back together to pull in the garage and they worked! Any ideas?
Steve

Could be your ambient light sensor (the little red plastic dome in the center of the dash). If it's going bad, the BCM may be having trouble deciding if it's day or night to run the daytime running lights or headlights. (You don't have ballcap thrown over it do you?;) )

won't go on with the switch either.
Steve

In that case, I'd suggest having the dealer check out the switch, sensor and wiring connections to the BCM (it's in the dash just above the driver's knee). You've got some kind of a gremlin in there somewhere.

swap the relay with another one like the fog relay. maybe it's bad and when you hit a bump it connects again??

just a thought

-mike

Most problems seem to be a poor ground connection, maybe on the JK harness, which I believe has two grounds. There's a lot of plastic on the front end.
Did you try swapping the two relays on the JK harness?
Do the lights work on High Beam?

Switched the relay when the lights were not working, no change. Lights will go off with just low beams (two lights) or high (four lights). The light switch itself in hot, but has been since new.

Thanks for the input guys. Every time I go out to work on the problem, the lights work.
Steve