First off, everything else electrical works on my car and the system has never been messed with at all. The only additions I've done to the car have been Dave's harness upgrades. My problem is both rear turn signals are not working. I've tried to trouble shoot them and I'm by no means a wiring guru. No luck so far. Would a bad rear chassis ground cause this? Any thoughts???

1) Do the front turn signals work?

2) Do the rear signals turn on when the hazards are on?

Yes, the fronts work but the rears don't work under any condition. I'm kinda stumped...

If the rear turn signals do not work with either the hazards or the turn signal themselves, then I would look for a point of commonality between the circuits. Have you checked the plug that goes to the rear turn signals that is located under the passenger-side vent on the right-hand side of the dash?

The rear turn signals are common with the brake lights starting at the combination switch. Do the brake lights work?

The brake lights have a fuse common to the hazards.

The turn signals are on the ignition fuse.

The turn signal circuit passes through (in this order):

the hazard switch

the turn signal flasher

the turn signal switch (combinaton switch)

and a handfull of connectors along the way.

A bad ground at the rear could cause the problem but will affect the brake lights, tail lights, and reverse lights as well.

Actually, the turn signals do not pass through the hazard switch from the combo switch. If you look at a wiring diagram the wires from the combo switch connect to the wires coming out of the hazard switch. 240zs are odd ducks with regards to their turn signals. They have 4 wires from the combo switch and hazard switch, one for each light.

Actually, the turn signals do not pass through the hazard switch from the combo switch. If you look at a wiring diagram the wires from the combo switch connect to the wires coming out of the hazard switch. 240zs are odd ducks with regards to their turn signals. They have 4 wires from the combo switch and hazard switch, one for each light.

Yes and no. I was refereing to the circuit starting at the fuses, before the combo switch. Your reference is to the wires going to each lamp, after the combo switch. Both seem to be correct.

Try looking at this: Hazard Switch ? Brake Light ? Turn Signal Circuit Analysis | Fiddling With Z Cars

Thanks for the tips guys. I'll skin this cat yet...

OK, so I took the connection apart under the dash per KTM's suggestion and started there. Hooked up my test light to the G/B and G/R wires and I'm getting power, but barely enough to light the test light bulb. Any ideas???

There are many connectors under the dash. Which one did you take apart? Does it match up to any of the connectors in the link I provided?

Yes, I took apart the proper connector for the rear turn signals. The color codes match the diagram