Darrel Toepfer wrote:

Hankal wrote:

In the meantime can any one give some advise.

If you are stationary and not in transit and engine off, does it still
trip the breaker? If not, sounds like a chaffed line that might be
shorting out somewhere along its path to the light - from the switch...

Unless it's an erratic short caused by vibration, that will result in the immediate
tripping of the breaker. Sounds to me (as someone else also said) that something's
heating up and causing the delayed trip. In my experience, that's frequently caused
by a poor ground connection.

I do agree with you that the problem is between the breaker and the light ground
connection. Could also be the switch.

I usually troubleshoot these things by moving the load further up the circuit until
the problem disappears. At that point, I've isolated the problem. In this case, I
would use sandpaper to polish the ground connections. If that didn't correct the
problem, I would remove the bulb, attach temporary leads, and hook it up directly to
the switch. If the breaker doesn't trip after a reasonable period of time, the
problem is in the wiring to the light fixture. If it trips, disconnect the switch and
hook the light up to the switch wire. If the breaker doesn't trip, the switch is the
problem. And so forth.

Now. If you wind up with the light hooked directly to a brand new breaker and the
breaker trips, I would be somewhat at a loss.

George Patterson
If you want to know God's opinion of money, just look at the people
he gives it to.