Brake Lights..etc..

[biggus]

77 M880, lights turn signals work. Emerg. flashers do not work.

Brake lights did not work. have hot feed to brakelight switch, but white wire running to back showed it was shorted with tester.
Ran new wire from the switch to back wiring harness and tied it in to the 2 yell/stripe wires and presto, have brake lights.

Problem; when I turn on left turn signal with the brake lights on, the signal does not work. Left signal works fine with headlights and all other times, just when you press on the brake pedal.

Any idea's??
Did I hook the new brake light wire to the wrong wires in the rear?

Thanks in advance.

 

[goodbrewing]

The tail lights should be both the combo brake/directional and the parking light. 1 wire goes to each and the ground is through the mounting bolts. Most of the times I have problems it is a bad ground. You can still have 1 filament working but it gets its ground through the other wire somehow and if you have both the brakes and the parking lights on it goes out. I hope I didn't confuse you too bad.

 

[biggus]

Just when the brake lights are on, the left turn signal quits.

Another question is where can I find a fuel sending unit for this?

 

[Dave_1972]

Bad ground through the mounting bolts caused similar issues for me when I installed a new wiring harness. So I cheated - and ran a ground wire from cab/frame and bed/frame. Haven't had a problem since.