Turn signal issues

[44CCKW]

I,ve got a 77 M882.All of the lights work on the truck as does the blackout light system.The issue is the turn signals do not work.I have replaced both flashers and all the bulbs in the truck still nothing.Do you think this is a main blackout light switch issue?or just a bad relay somewhere.I have also replaced the relay that bolts to the dash near the parking brake,And the signal switch wire harness in the steering column.Still no go.

 

[NDT]

How about the column switch itself? If the rest of the lights work, that means the 3 lever switch is fine.

 

[44CCKW]

I have replaced the column signal harness with another one I had,Because the signal arm would not return after a turn.But,The signals did not work before I replaced this and I had hoped replacing the harness would cure this issue.I did get them to work for a very short period by messing with the wires that go to the small circuit breaker box down by the E brake release arm.I do think that this is part of the blackout light system.Oh,When I put on the left turn signal,The rear left tail light goes out???

 

[goodbrewing]

It sounds like bad grounds. Pull the lights and check for a rusty screw on the ground wire or a broken wire. It could also be a rusty bulb socket.

 

[44CCKW]

Just checked the flashers and they work fine,But still no turn signals.

 

[NDT]

Sounds right goodbrewing. Do the brake lights work? As these trucks use the usual 1157 bulbs, the turn signal will flash the brake light. If brake and turn signals cause the marker (tail) lights to do funny things, for sure grounds are the culprit.

 

[44CCKW]

Brake lights work fine.

 

[goodbrewing]

What do you have if you turn the parking lights on and step on the brakes? With the duel filament bulbs 1 filament is the parking light and the other is the brake, flashers and directional. If you have a bad ground 1 can work until you turn on the other and then neither will be lit. It sounds like that might be what happened with the rear left.
If you have gotten the rest of it to work by wiggling wires it could be a broken wire or bad connection in a plug or component. I haven't been under the dash of one in awhile so I am not sure what the circuit breaker thing is you mentioned. Can you post a picture of it?

 

[44CCKW]

Just a up date.I got the turn signals working.But,They do not work when the head lights are on????