2007 peterbilt 387 drive low beam headlight doesn't work?

srarter with the basics. take a test light and check to see if your getting power coming out of the plug, then check ground. when you find which one is bad remember the color of the wire and trace the harness back to the next plug or connector, probably behind bumper or on frame and poke the wire there to see if you have power/ground there. that'll help you narrow it down.

 

just a thought. I think the 387 has a single headlight bulb for hi/low. if your high beam works then the ground should be good, I'd focus on the low beam power wire.

 

Check your fuses. Most Petes have separate left/right & high/low, giving you 4 fuses for you headlights. I've seen a bunch of 379's that had fuses fall out. If ones missing, it's probably fell under the fuse panel. You may have to get a little pick and bend the tabs tighter or replace the wire ends (not fun). If that's not your problem, check for power at the fuse and trace wires.

 

With a test light check both sides of fuse or breaker. Then like dustinbrock said work back from plug.

 

Can i know what was the problem, 'cause i have the same issue now on my 2016 348...

 

Can i know what was the problem, 'cause i have the same issue now on my 2016 348...

 

Anyone figure out the issue I have it happening on an 08 388 right now can’t figure it out

 

Micro relays unplug them plug them in again ,if they are old replace all of them.
It will solve your problem.