85 turn signals and running lights

[BrianX128]

For no reason my turn signals have stopped working when my running lights are on. Everything works fine when they are off but when they are on the turn signals flash dimm back and forth on both sides of the truck and the reverse lights come on.

If I turn the reverse lights on then the running lights in the rear turn on.

 

[franklin2]

You have grounding problems. Pull all the bulbs and clean the sockets. Your year still uses the round brass looking bulb? If so, that brass part is where it grounds so make sure the tab in the socket is clean and touching the outer brass part of the bulb which should be cleaned also. I have had the sockets go bad also. You can take a ohmmeter and pierce the black ground wire leaving the socket, and the tab in the socket, to see if you have continuity.

 

[BrianX128]

Yep you win. Black wire would not ground on either side of the turn signal bulb holders in the rear. Spliced in a ground on both sides to a self tapper screw inside the metal where the assembly goes into and all the weirdness went away.

Easy fix, long diagnosis time lol.

 

[IDIBRONCO]

Easy fix, long diagnosis time lol.

I thought that was a long term diagnosis/fix?

 

[franklin2]

Yep you win. Black wire would not ground on either side of the turn signal bulb holders in the rear. Spliced in a ground on both sides to a self tapper screw inside the metal where the assembly goes into and all the weirdness went away.

Easy fix, long diagnosis time lol.

You are good as long as the bed stays grounded to the frame and the frame is grounded. I think the factory ran a ground wire all the way up front to under the dash for all the rear wiring.

When I have used the bed for a ground, I have had to occasionally bolt a jumper wire from the bed to the frame. And then you need to make sure the ground for the frame up front is good. On the gas trucks they had a bare spot on the large ground wire and had a metal clamp that bolted to the frame as it made it's way from the battery neg to the engine block.

Not sure what they did on the diesels, I know they have a large ground wire from each battery going to the front corners of the block on each side. But this is no good for the frame or the body, the engine/tranny/trans/rearend are all mounted in rubber mounts. And the body is mounted on rubber mounts. The factory had ground jumpers here and there to ground everything, but sometimes they get left off or get corroded.

 

[chillman88]

Not sure what they did on the diesels, I know they have a large ground wire from each battery going to the front corners of the block on each side.

On the block end they each have a 10ga or so wire going to the frame.

 

[riphip]

On the block end they each have a 10ga or so wire going to the frame.

Needs grounds from frame to body cab & bed also for lights to work properly

 

[chillman88]

Needs grounds from frame to body cab & bed also for lights to work properly

Yes but franklin was talking specifically about the frame ground in his post.

 

[riphip]

You are good as long as the bed stays grounded to the frame and the frame is grounded. I think the factory ran a ground wire all the way up front to under the dash for all the rear wiring.

When I have used the bed for a ground, I have had to occasionally bolt a jumper wire from the bed to the frame. And then you need to make sure the ground for the frame up front is good. On the gas trucks they had a bare spot on the large ground wire and had a metal clamp that bolted to the frame as it made it's way from the battery neg to the engine block.

Not sure what they did on the diesels, I know they have a large ground wire from each battery going to the front corners of the block on each side. But this is no good for the frame or the body, the engine/tranny/trans/rearend are all mounted in rubber mounts. And the body is mounted on rubber mounts. The factory had ground jumpers here and there to ground everything, but sometimes they get left off or get corroded.

Yeah, he had it covered.