Turn signal switch woes

[65ChevyC20]

I'm having an issue with a turn signal switch, I'm hoping someone can steer (lol) me in the right direction.

I recently replaced my OEM turn signal switch in my truck with a aftermarket switch. Everything worked well for a few weeks and then it shorted out and melted the wires, (unit on the right). I thought i pinched a wire while tightening things down.

I ordered a second harness from another supplier and installed that one, (unit on the left). Made sure that no wires were pinched or grounded. This one worked fine for a period of time and then it melted like the first unit.

As you can see only the purple and green wire melt, not sure what the wires feed that causes the wires to short out. I dont have a wiring diagram to figure out where they go. The wires do not melt past the point where the aftermarket connector plugs into the OEM connector at the base of the steering column.

I dont want to purchase another harness if this is what is going to happen.

Another thing I want to mention is that I did do the jumper wire modification to allow my parking lights to stay on when the headlights are on. I have since pulled off the jumper wire, do you think this could be the issue?

https://photos.app.goo.gl/7T5v2JqrB32n1TiG7

[The Rocknrod]

Looks like the green wire is the right rear and the purple from the fuse panel flasher:
https://67-72chevytrucks.com/vboard/...0&postcount=12
Clearer one:
https://67-72chevytrucks.com/vboard/...3&postcount=32

[ACK]

Looks like there's a short in the system, here's a video that might help ya' ... https://www.youtube.com/watch?v=9wLrTjeb9TY

If there is a short in the turn signal, trace the green wire from the harness all the way to the rear of the truck and see if you can find any exposed wire, cracked casing, or splices. If everything looks 100% solid, the issue could be with the rear harness (pretty unlikely), the tail light, or an add on (eg: a harness for trailer turn signals). Good luck.

[VetteVet]

Originally Posted by 65ChevyC20

I'm having an issue with a turn signal switch, I'm hoping someone can steer (lol) me in the right direction.

I recently replaced my OEM turn signal switch in my truck with a aftermarket switch. Everything worked well for a few weeks and then it shorted out and melted the wires, (unit on the right). I thought i pinched a wire while tightening things down.

If you had pinched a wire, it would have shorted right away, your picture definitely shows the purple wire and the green wires burnt. The purple wire is the power wire for the turn signal wires which are the dark green and the yellow wires. The purple wire comes directly from the flasher to the half moon plug at the base of the steering column, and the green wire goes from the same connector to the firewall connector and then to the rear harness to the passenger side tail/stop light. any bare spot on it that rubs a ground for very long while the right turn is selected would cause a direct short to ground resulting in too much amperage flowing through it and the excess heat resulting would burn the insulation like you see.
If you have a short in the turn signal switch, it would have to be to a ground and it would be intermittent and it would have to be on the green wire as well. I would check inside the column near the switch for a weld spot on the column shaft that might be rubbing on the green wire. Most likely it is on the rear harness somewhere.

I ordered a second harness from another supplier and installed that one, (unit on the left). Made sure that no wires were pinched or grounded. This one worked fine for a period of time and then it melted like the first unit.

As you can see only the purple and green wire melt, not sure what the wires feed that causes the wires to short out. I dont have a wiring diagram to figure out where they go. The wires do not melt past the point where the aftermarket connector plugs into the OEM connector at the base of the steering column.

I dont want to purchase another harness if this is what is going to happen.

There is a black wire in the column harness that goes to the horn plate and is grounded to the steering column shaft when the horn button is pressed. It activates the horn relay by grounding it to the column shaft. It should not cause the short you are seeing. There may be a way for the green wire to rub on the column shaft or there might be an insulator for the signal switch that is out of place. I haven't looked at one in so long I don't remember.If you could put the bad switch back in place and put the switch in the right turn position. You could check for continuity between the green wire and the column shaft. I don't suspect the purple wire because there would be other wires affected. The yellow left turn wire and the right and left front signals for instance.

You would be well served in case you don't solve this dilemma to install a fuse holder in the purple wire before it plugs into the column connector. The factory didn't put one in the turn signal circuit. There is one for the stop and tail lights but not in the turn signals. It would seem that if the green wire was grounded to the frame it would blow that fuse since it is the same wire as the turn signal wire. That points to the problem being in the column or in another faulty turn signal switch.

Another thing I want to mention is that I did do the jumper wire modification to allow my parking lights to stay on when the headlights are on. I have since pulled off the jumper wire, do you think this could be the issue?

The tail light wires are all brown and they are not connected to any part of the turn signal column . They are fused by the stop/tail/dome hazard/fuse.


https://photos.app.goo.gl/7T5v2JqrB32n1TiG7

I hope I have been some help.