M-923 Headlight electrical short

[scotttigchelaar]

Hi, I have an M-923 early '80's model. One of the headlights keeps blowing... within an hour of replacement. Have been told it's a common problem. Anyone with advice on a fix? Much appreciated!

 

[porkysplace]

Have you checked and cleaned the grounds ?

 

[scotttigchelaar]

Will try that. Is each headlight grounded separately, near the fixture? Was going to replace with LED headlights... since they're more rugged... but they're also expensive so I don't want to damage one of them if the problem is beyond vibration or something like that.

 

[M543A2]

Trace the wires out of the headlights to the ground bolt, probably nearby on the front bulkhead the lights mount to. I have even run a new ground wire from that ground to the frame and motor to assure all is grounded securely. That is what I did on an M37 with the same problem and it fixed it.

 

[scotttigchelaar]

Trace the wires out of the headlights to the ground bolt, probably nearby on the front bulkhead the lights mount to. I have even run a new ground wire from that ground to the frame and motor to assure all is grounded securely. That is what I did on an M37 with the same problem and it fixed it.

Awesome!

Thanks so much!

 

[lindsey97]

Awesome!

Thanks so much!

What he said. Each headlight is grounded with a short jumper near the back of the headlight, on the hood. Run a secondary wire for ground to each headlight, then ground to frame, continue on to starter and ground there where main ground bolts to starter. I even added additional ground wire from starter to alarm box under dash that alerts low air or park brake set. Then from there I ran a ground wire to the fuel tank. Also make sure the bed is grounded to the frame.

Be absolutely sure to ground the hood to the frame and clean the ground bolts/hood if you are installing new LED Trucklite headlights. Rumor is they don't last long with sketchy ground.