turn signal fuse keeps on blowing

[lsukevinc]

As soon as i stitch on the ignition switch, the fuse (15 amp orange wire with yellow stripe) blows immediately. Last night i tried unplugging both flashers and it still blew up as soon as i turned on the switch. What is weird is after i plugged back both flashers, i decided to try the emergency flasher and they work fine. All of the parking lights work fine with the fuse blown as well. What could the problem be? The orange wire is still wrapped in black tape in the main harness from the factory. Could it be a problem with the turn signal switch?

When the fuse blows, i believe the turn signals are the only thing that does not work.

 

[Steve83]

What year is the wiring harness? Turn signal wiring changed. Be specific.

 

[Viperwolf1]

W/S washers, original radio power wire, and backup lights share that fuse. If you pulled the flashers and the fuse still blew it's probably one of the other circuits causing it.

 

[TN1776]

You have a short to ground somewhere. Maybe a wire inside the column has been rubbing and is now without insulation, grounding to the column... just a guess.

 

[DirtDonk]

The parking lights and flashers work without the ignition in RUN. The other items need the key on, but you say that the fuse blows as soon as you turn the key on. But you don't say whether your switches are engaged or not, so for now I'll assume not, which means that it's one of the power feeds to those circuits and only the keyed circuits.

Because the hazards work, it's not any of the wires between there and the lights, which would seem to eliminate anything in the column for now.

For the rest, I'll wait to hear what year your truck is.

Paul

 

[lsukevinc]

It is a 76 with factory wiring harness. I did swap out the fuse box for a newer one., but that never caused a problem before

 

[suckerpunched]

W/S washers, original radio power wire, and backup lights share that fuse. If you pulled the flashers and the fuse still blew it's probably one of the other circuits causing it.

you could also unplug the 4 wire connector behind the left valve cover that goes to the Neutral safety and backup light switches and at least eliminate that part of the backup light circuit. engine wont crank with nss connector unplugged but the key would still power up the circuits you are working on.

 

[half cab]

I know this sounds crazy but I had this same problem bout 5 yrs ago n tried everything and ended up cleaning up my dimmer switch and the crude at the floor board and they have worked fine ever sense?

 

[DirtDonk]

...I did swap out the fuse box for a newer one., but that never caused a problem before

That's a bold project on some of our rigs!
But even though it's never caused any trouble before, it would be well worth looking at it to see if there are any loose connections or corrosion you didn't see before, or something wearing out from rubbing or being bent too tightly.

Worth a little look-see behind the glovebox I would guess.
Or did you move the fuse box to somewhere else at the same time? Was this a stock replacement, or to a later style fuse arrangement?

Paul

 

[lsukevinc]

I know this sounds crazy but I had this same problem bout 5 yrs ago n tried everything and ended up cleaning up my dimmer switch and the crude at the floor board and they have worked fine ever sense?

I actually thought of that too. I unplugged it and
Still blew the fuse. I'll try unplugging some of the other items like someone suggested.

 

[Steve83]

That fuse feeds the radio, reverse lamps, turn flasher, and w/s washer. For it to blow as soon as the key is turned on, there must be a wire pinched between the fuse & those items, or a fault inside at least one of them. If it's past them, the fuse wouldn't blow until they're turned on.

 

[lsukevinc]

It ended up being a bare wire from the 4 prong plug under the hood. I assume it has something to do with the reverse lights?? Anyway, hack job by the previous owner I never noticed until today. Thanks for all who suggested things to look for.