Electrical Nightmare Please Help

[Grapdawg]

Ive got a electrical nightmare, Ok so here are my symtoms.

Headlights on blinkers wont work at all.
Headlights off blinkers work but both rear blinkers blink.
Step on brakes with lights off and dash lights light up.

Any suggestions?

[kwplot34]

Time to check all the grounds,and check all the wires for shorts, but i would make sure all the grounds are good first,bad grounding can cause some funny things to happen.

[mr48chev]

It does sound like a ground problem with the taillights.

One more thing to check that tends to cause problems on these trucks is a cobbled up trailer wire connection that someone put on at one time or another. Those can be a prime source of shorts and messed up connections if they were not done right.

[kwplot34]

Originally Posted by mr48chev

It does sound like a ground problem with the taillights.

One more thing to check that tends to cause problems on these trucks is a cobbled up trailer wire connection that someone put on at one time or another. Those can be a prime source of shorts and messed up connections if they were not done right.

That is a very good point,and a good place to check. the wiring on these trucks is pretty simple, i also just remembered,make sure the ground strap from the engine block to the fire wall is connected,not a bad idea to take them off and clean them,or replace them.

[Longhorn Man]

i would start off with new bulbs and checking the grounds

[Grapdawg]

Thanks all I will post up some pics of the mess that is in the back. I think it may be a trailer light setup. Also does the engine have to be grounded to the firewall or can it be the frame?

[soule64]

I had similar issues when installing a new Painless harness. Turned out to be ground issues. I grounded 4 places: engine-chasis, engine-frame, chasis-frame, bed-frame. All with braided straps, cleaneaned to bare metal and coated with dielectric grease. No problems now.

[Classic Heartbeat]

Sounds like the headlight switch has failed and you are getting electrical feedback through it once you turn your headlights on. Replace the switch and also check your grounds like everybody else says. I had a simeler problem on the Blazer that is in my shop now, but the new headlight switch solved it. WES

[Grapdawg]

Originally Posted by soule64

I had similar issues when installing a new Painless harness. Turned out to be ground issues. I grounded 4 places: engine-chasis, engine-frame, chasis-frame, bed-frame. All with braided straps, cleaneaned to bare metal and coated with dielectric grease. No problems now.

Ok I have the Engine-Frame and Bed-Frame Were would I ground the Engine to Chasis and Chasis to frame. Im sure they are there somewere. This sucks. I think it may have to do with my turnsignal switch as well but not sure as it is very worn out. I did however replace the voltage reg and had my alternator tested. Found a bad ground to it but now that is resolved. So im stumped I guess I will go through all the grounds and see if I can find those other grounds. there were 3 black wires on the back of the truck that were just hanging there. My brake lights didnt work until i twisted them together. Thanks for all the great help as always.

[kwplot34]

Yes you need ground straps from the frame to body and motor to body,or else the only ground path is through the body mounts and that is not a good ground path.

[soule64]

On mine, the engine-chasis was on the p/s cylinder head to a large machine screw on the firewall. The Chasis-frame strap went from the p/s fwd cab support to a hole in the top of the frame.

[soba_03]

Originally Posted by Classic Heartbeat

Sounds like the headlight switch has failed and you are getting electrical feedback through it once you turn your headlights on. Replace the switch and also check your grounds like everybody else says. I had a simeler problem on the Blazer that is in my shop now, but the new headlight switch solved it. WES

I agree, I had a problem exactally like you have. I too found that it was headlight switch. Over the years it got some corosion in there cleaned up the plug and switch and solved my problems. Unplug you headlight switch and look at the plug them grab a flash light and look at the light switch or pull it out and take a good look at it..

Good luck...