Trailer lights keeps going off?

You have a short/high amperage draw some place. Unplug the trailer and see if it still does it. If it still does it unplug the cord on the truck side. If it stops replace the cord. But if it stops when the trailer is unplugged the problem is in the trailer.

 

That mechanic is a retard.

 

Ok that mechanic is a I d I o t.

 

Huh??

 

Sound to me like a short.

 

He has a short or high amperage draw on his parking light circuit that is causing the circuit breaker to trip under the dash. So with the parking lights on he needs to unplug the green cord from the trailer. If the breaker stops tripping the problem is in the trailer.

If it does not stop tripping when he unplugs the cord then then he needs to unplug the cord from the tractor. If the breaker stops tripping then he needs to fix/replace the green cord.

After unplugging the cord from the truck the breaker still trips then his short is in the tractor.

This has nothing to do with the alternator, starter or the fact he needed a jump the other day.

 

Im betting the test box didnt have fuses/circuit breakers in it.