Peterbilt 389 Dim Headlights

You have a bad ground somewhere, check for breaks in the ground wiring and clean all ground wires.

 

Can you unplug your headlights and check your voltage with volt meter at the light? If you have proper voltage than yeah, that’s all she’s got. I own a 379 and low beams aren’t that great at all, to be honest, I used a buddies Mack last month and another buddies western star. Neither one of them could I see a #### thing. I wound up just keeping high beams on all the time. 389 seems to be too new of a truck to have grounding issues. I’ll bet it’s just the nature of the beast

 

I’m lookin at that beast and I’m sorry to say, those look normal to me. Bada.s.s truck either way dam

 

Yeah just doesn’t make any sense these days. Anyhow, just check voltage in the harness or the wires with a sewing needle. Just for piece of mind

 

They may need aiming a buddy complained about his all the time and someone showed him how to aim them and he loves them now .. apparently it takes a bit of work to do it but worth it he said

 

Under the cover I think he said there was a adjustment wheel but I may wrong