No reverse lights, charge light on voltmeter turns on when shifting to reverse

[Nola280]

Hi y'all,

Sorry if this is a repeat, but I haven't been able to find an issue quite like this in the forums.

I've got a '76 280z that I purchased with a 5 speed from a later car already installed. The reverse lights stopped working a few weeks ago, so I checked all the connections, replaced the switch, swapped bulbs, and I still get nothing. The strange thing is that when the car is running and I shift into reverse, or press the switch manually without it being installed, the red "charge" light in the voltmeter comes on. There is some voltage coming through at the sockets, but not a full 12 volts.

All other lights and switches function perfectly, I've checked the FSM to insure that the wires I'm plugging into the switch are the right ones, and I know they're the same ones that came off the old switch because I removed the old one and installed the new one myself.

Has anybody out there experienced anything like this? Any help at all would be greatly appreciated.

Thanks!

[Zed Head]

Is the engine running when the charge light comes on? Or is everything off? The reverse switch just completes a circuit, allowing power to flow through the reverse lamps. Seems like you might have a short somewhere between the switch and the lights, maybe drawing enough current to overload the alternator at idle, or actually shorted through the Charge lamp wire.

[Nola280]

Charge light only comes on with the engine running, nothing happens if the ignition switch is set to On without the motor running.

I'll try to trace the harness the rest of the way back and see if I can find a short.

I've never been much good at electrical work. Any tips or common issues to look for while I'm poking around in there? If I've got to dive into it, I want to make sure I get everything done that I can while I'm in there.

Thanks for the help!

[Kurbycar32]

I've never been much good at electrical work. Any tips or common issues to look for while I'm poking around in there?

Thanks for the help!

Use an actual voltmeter, not a test light. Don't use crimp or twist type electrical connectors, instead use solder and heat shrink whenever possible. When I did my 260z I opened every single connection cleaned with both electrical contact cleaner and a nylon brush and reassembled. Between that, cleaning every ground connection and replacing one bad wire that a PO installed to bypass my brake light circuit all of my gremlins went away. Action photos here:

https://sites.google.com/a/thecomputerrehab.com/260z/electrical

[JeffMopar]

Hello All,

Just a quick thought. Make sure your ground near the bulbs is clean and has a good connection. Having a bad ground shows as crazy syptoms when the power tries to find an alternate ground. Hope that helps.

Jeff