Head lights

03 peterbilt 379 same dam thing .
Replaced all 4 headlights
2 low
2 high.
Replaced turn signal switch.
Fuse is good
Relay new
Still no lights.
Any idea would be helpful thanks much in advance.

 

Got power where the wiring plugs under radiator ?
Run a ground wire to headlights.
Had same problem when I put new led headlights in a few years ago.
Lost the ground

 

Thanks for the info.
Had already checked that and spliced a shaky wire.
Looked behind dash at light toggle and saw it had melted alittle. Replaced it and put connectors on wires .
Hard wire so to speak and bingo lights.
Dam I was ready to throw in the towel and pay someone to fix it.
I got lucky. .
Thanks for the tip just the same.

 

Might want to change that fuse. It should of tripped..

It's always something.

 

Did you go from Halogen to LED? Some require you wire the lights differently.

 

At a former company a co worker ended up adding a marker light under the hood to provide a constant draw on the circuit. His new led headlights would flash otherwise due to the low power draw it messed with his headlight relays or ecm somehow.

 

"Constant draw on the circuit" you do that to get around the speed limiter the company likes to punish you with. Shhhh, ancient Chinese secret.

 

No not a fan of led headlights