electrial problems.

peanutman · Post by **peanutman** » Mon Jan 14, 2008 3:51 pm

Maybe someone can help me. having problems with emer flashers, turn signals, dash lights. Thought it might be the printed circuit on my 70 f-100. Replaced and still same problem. When i turn headlights on, left blinker indicator comes on, when left blinker is on and i turn on headlights indicater stops and remains lite. Everything is orig and never had any wiring done. Could i have a short or a ground problem. Also with headlights on when you turn on emer flashers all ext lights pulsate slightly. The guy i bought truck from has wired for trailer light hook up. looks sloppy. Could this be my problem

72stepside · Post by **72stepside** » Mon Jan 14, 2008 4:58 pm

Just off the cuff it sounds like a grounding problem to me.

peanutman · Post by **peanutman** » Mon Jan 14, 2008 5:16 pm

Thanks 72 stepside thats where everyone is telling me to start.

Thunderfoot · Post by **Thunderfoot** » Mon Jan 14, 2008 5:20 pm

72stepside wrote:Just off the cuff it sounds like a grounding problem to me.

First thing to look at would be all the major grounds and then the trailer trailer wire add in would be the next thing alright...

peanutman · Post by **peanutman** » Mon Jan 14, 2008 5:29 pm

THANKS THUNDERFOOT

bluef250 · Post by **bluef250** » Mon Jan 14, 2008 6:02 pm

Also check bulbs and their sockets.

fordman · Post by **fordman** » Mon Jan 14, 2008 7:20 pm

this sounds like something feeding back through something else. so a bad ground could be correct. my first thoughts are always the turn signal switch when i read about these kind of problems. but i could be wrong.

l1k2gadd · Post by **l1k2gadd** » Mon Jan 14, 2008 9:15 pm

An incorrectly wired trailer plug could back-feed power to any point in the truck. Is the trailer plug the type that has the lights in it that illuminate when different things like the brakes and turn signals are used? You have parking light, turn signal light (both), headlight, reverse light and ground connections at the back of the truck.

If anybody has ever noticed, when a brake light burns out it will back-feed through the parking light and still makes it appear like both of your brake lights work. When you turn your headlights on you won't have a brake light on that side. If both filaments burn out the reverse light will illuminate on that side when you apply the brakes.

I have seen an incorrectly wired stereo do things like you are mentioning in a 1967 Mustang. It was freaky because all kinds of lights would light up when the key was just turned on. Power was back-feeding from the radio hot and instrument lights wires (and I forget which other wires might have been in the mess) that were tied together at the stereo.

If the former owner spliced wiring together back there to get the trailer plug working and wrapped each wire with electrical tape and then wrapped all of them together in a bundle with tape there could be stray wires poking through the tape causing cross-connections between the wiring back there.

peanutman · Post by **peanutman** » Mon Jan 14, 2008 9:19 pm

fordman i just installed a rebuilt steering column in this truck. It came with new signal switch. I repinned the connector and all wires matched per color code. this problem existed before replacing column. Is there a ground that goes to the insterment cluster?. Could it be a bad headlight switch. Also my insterment panel lights are not working. All this was going on before i replaced the printed circuit and colomn.

peanutman · Post by **peanutman** » Mon Jan 14, 2008 9:25 pm

No just a crude 4 pin trailer light connector. This week end i will disconnect that and see if it helps. I am at a point where i am getting frustrated trying to figure this out .i feel like im missing something simple.

fordman · Post by **fordman** » Mon Jan 14, 2008 9:26 pm

yes the inst cluster does have a ground on the back of it. it hooks to the dash support behind the cluster. i would check the dash light fuses. a bad headlight switch will make the headlights shut off and then back on in a few seconds. bu tthey wont flash like a turn signal if the switch is bad.

Thunderfoot · Post by **Thunderfoot** » Mon Jan 14, 2008 9:30 pm

The Headlight switch is a separate circuit from the turn/brake lights... There is a fuse for the instrument light in the fuse panel. The power for them does come from the light switch and then goes to the fuse before going to the instruments, if you don't have power going to the fuse box for the fuse then the light switch could be bad. Also, if you haven't, try working the dash light dimmer on the light switch sometimes they get corroded...

peanutman · Post by **peanutman** » Mon Jan 14, 2008 9:37 pm

THIS WEEKEND GONNA PULL CLUSTER BACK OUT AND CHECK ALL WIRING HARNESSES, PULL ALL BULBS, GREASE SOCKETS AND CHECK ALL GROUNDS IN PROCESS. I REPLACED ALL BULBS AND VOLTAGE REG IN INSTRUMENT CLUSTER LAST WEEKEND.

peanutman · Post by **peanutman** » Mon Jan 14, 2008 9:42 pm

Thunderfoot when i turn headlights on left turn signal indicator lights up. Crazy-can't figure that out. Having heck tracing wires. I need a good wiring diagram on paper at i can look at and trace

peanutman · Post by **peanutman** » Mon Jan 14, 2008 9:46 pm

Fordman you may have the answer. There is no ground wire. Was not one when i removed the cluster. Where does it connect to cluster?

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