Turn signal issue/ brake light issue

[Ifyasquintitsmint]

My rear turn signals do not function, also my passenger side reverse light doesn't function.

I have cleaned ground (driver taillight ground, is there any others?), and tested the bulbs by swapping known good bulbs. I am not getting any power to any of the 3 bulbs.

I'm thinking this is two separate issues, with the passenger wire being broken at some point in the line. What would cause the rear turn signals to not function? The front works perfectly.

Is there anything else that could cause the passenger side reverse light not working?

EDIT: I've done some reading and going to swap the flasher/hazard relays to see if that's my issue.

 

[Curt]

Well,I think you’re right about a broken line,bad connection.

Yes,that’s the only ground on the tail section from factory.

I would think it’s most likely from the end of the frame,where it plugs and Ts off to each side.

 

[Turbo4whl]

What Curt said ^^^

Could be many things from the brake light and turn switches to the wiring. Since one backup light works and one does not, I would start at the 4 pin rubber connector plug at the driver's side rear frame connector. See what power you have there. From that plug seperate wires run to each taillight assemblies and the tag light. This is where someone could tap in for trailer lighting. See if anything is spliced there.

 

[Ifyasquintitsmint]

Looks like the tails have been spliced into. I have a all steel tow bumper and some setup that I'm not familiar with.

I have 12v to the single prong on the rubber grommet. I cant tell which wire the prong is associated with. Should I be getting 12v to any other prong?

PO made a mess of the wiring in the cab so I am sure itll be fun to track down.

next step is to test the wires at the column correct?

 

[CRM]

Yours is an 84 but here is a wiring diagram for my 85. Looks like the wiring is the same color.

You must be registered for see images attach

 

[Matt69olds]

Push and pull the hazard switch button several times. That sometimes gets taillights working again. If not, read on.

Get a cheap 12 volt test light. Check for power at the yellow wire (left turn) and green wire (right turn) of the turn signal switch at the base of the steering column. If the light flashes with the turn signal, the problem isn’t the switch.

Find the green and yellow wires at the firewall electrical (near the brake booster) connector. There will be a dark green (right turn) light green (reverse) brown (taillights) tan (fuel gauge) yellow (left turn) check for power on each wire while operating the circuit in question. Keep working your way back, eventually you will find the break in the wires.