No Reverse Lights

Reverse lights no longer turning on in my 5-speed and I researched all the troubleshooting here and still can't get them to work. I tested for 12V at the lead to the reverse switch and am getting power so it is not fuse 16 or anything upstream of that. The LG/W wire is getting 12V with the key in the ignition. I jumpered the switch leads to test if it was bad a bad switch and still no reverse lights. With the switch jumpered I tested for 12V at the wiring harness for each taillight and did not see 12V on the connector for the reverse light -- so somewhere between the reverse light switch and the taillight wiring harnesses. Any ideas? I did check for cut wiring but have not come across anything. All other lights work fine. No other electrical problems.

there are two connectors in the section of wiring you refer to, one is a 2 pin plug on the engine harness, the other is the bulkhead connector. Make sure the terminals are clean. The wires could so be pinched somewhere.

Sounds like you are almost there - you have it narrowed down and the skill to properly troubleshoot wiring.

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Originally Posted by Josh

there are two connectors in the section of wiring you refer to, one is a 2 pin plug on the engine harness, the other is the bulkhead connector. Make sure the terminals are clean. The wires could so be pinched somewhere.

Sounds like you are almost there - you have it narrowed down and the skill to properly troubleshoot wiring.

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Thanks Josh. I checked and couldn't find in the Taillight Circuit diagram here in the forum where the 2-pin plug and bulkhead connections are located. I assume that is where the G/N wire from the reverse switch goes to before the taillights. Is there another diagram showing the locations of these two connections?

The other issue I thought might be one of the taillight boards. One is original (grey/brown color) and one is a replacement from Delorean-One (green PCB color). The replacement board is very clean, the original not so much. The original board (passenger side) appears to be upstream of the replacement board (driver's side) with regards to wiring. The other lights on the original board all work fine so the entire board is not out. However, I do notice a spot on the board where the reverse light socket is that is blackish, almost like a burn mark. I can't tell if it's dirt or a burn but it won't clean off. So my question is, if one board's reverse light socket is out, would that affect the other board? All bulbs are tested and working but neither right nor left reverse lights turn on.

Unplug the boards and check at the plug for +12 volts on the wire for the reverse lights. Be sure to have jumpered the reverse switch and turned on the ignition first. If you have power at the plug then the problem is the boards. A bad ground is unlikely since you say all of the other lights work. It is possible both boards are bad or the bulbs are bad. One bad board (or bulb) should not affect the other unless it blows the fuse. The boards are in parallel. Most people don't even know if their reverse lights work but it is good to have them working.

Check out the .pdf file HERE.

Thanks guys. With your help and the wiring diagrams I was able to locate and trace the G/N wire back to the engine compartment to the 2-pin white harness and bulkhead connection. I checked for pinched wires and nothing found. Upon inspection the 2-pin wiring harness terminals were very dirty. After cleaning them thoroughly, I tested and the reverse lights are fully functional now. The dirty wiring harness in the engine compartment was the culprit.

The 2-pin white harness is for the Frequency Valve. So, you might want to go back and check the black and red ones since they handle the reverse lights...you probably moved one of them or something else and helped a poor connection.

I have the same problem. Any chance for a picture where I can find that connection?

John

Attachment 57930
RED Plug:
G/N= Reverse Light Switch to reverse lights
LG/W= Power for reverse lights from fuse #16

BLACK Plug:
B= Ground for both Tail light assemblies
G/N= Reverse Lights

See .PDF file in earlier post for more...