My 02 3500 has a short in the driver's side turn signal circuit. No brake light or turnsignal in the rear. Only in the front and it flashes fast. I have disconnected the rear harness with no success. When I unplug the front turnsignal bulb, the flasher buzzes. I need the wiring schematic for under the dash and through the firewall. Also anything that people have found before with this problem also would be helpful. Not really how I wanted to spend my weekend, tearing apart the dash.

 

Hope this helps.

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First I would check the power wire to each rear bulb. Look for a slit in the wire where it is rubbing against ground. Check at the bulb sockets in the back, and if necessary, all along the loom from front to back. You may have a pinched wire somewhere. It happens if you have ever dropped the tank, or if you have a back ground AND you have a trailer hitch. I would check the grounds real close The brake light and turn signal bulbs are both dual element, so make sure you are tracing the correct wires. The sound from the flasher may be a short to ground. Since the bulb has two elements, the voltage will travel back thru the second element that is not being used. This means nothing if the ground is intact. I would trace the grounds on the tail light circuit. The flasher is cycling fast because more than likely there is a chaffed power wire or a broken ground. The flasher is basically shorting out.


My advice is the rear blinker, power wires first, then all the grounds. Check the wiring where it splits off to the passeneger side of the vehicle, in the back of the truck. You have to look closely to find the ground. Probably all black and thicker than the rest of the wires there. I cannot tell you what color your wires are because we have different years.


Good luck to you.

 

I also for got, remove the cowling around the steering wheel and check the wires at the bend if you have tilt steering. There seems to be quite a few problems with that area.

Good luck.

 

Found it, near the pivot on the steering column. Thanks for the schematic.