Reverse Lights Not Working

[DAZVI]

Hi, I have a 90 300ZX 5MT that is not getting power to the reverse light sockets. I confirmed I have an open loop at the plug when the transmission is in reverse. My understanding is that could indicate a bad reverse switch at the side of the transmission.

I have also read that an aftermarket reverse switch can be an issue by not having a plunger long enough to engage when the transmission is in reverse. So that has me curious, is there any possibility that a short shifter could be part of the problem? The previous owner installed one and I do not know anything about them. Just want to look at the most culprit

Thank you

[itsa300zx]

If your short shifter shifts properly into gear, then that’s not your issue.
Most likely as you said, the switch is the issue.
Disconnect the connector at the switch and check for continuity (should be open). Place shifter into reverse and check continuity gain, should be closed (and check for 12v power here too). If this is the case, then the issue probably lies in the wiring down stream to the lamps.

You can try applying 12 v to the body side of the switch connector to see if the lights work.

This transmission harness runs towards the front pass headlight via the starter and alt. check the 3 connectors behind the pass head lamp too.

[DAZVI]

If your short shifter shifts properly into gear, then that’s not your issue.
Most likely as you said, the switch is the issue.
Disconnect the connector at the switch and check for continuity (should be open). Place shifter into reverse and check continuity gain, should be closed (and check for 12v power here too). If this is the case, then the issue probably lies in the wiring down stream to the lamps.

You can try applying 12 v to the body side of the switch connector to see if the lights work.

This transmission harness runs towards the front pass headlight via the starter and alt. check the 3 connectors behind the pass head lamp too.

Ok thank you for confirming the short shifter. I have never had one on any car so I wasn’t sure if it could have caused anything.

I guess I’m going to just bite the bullet and tackle the switch. Fortunately this isn’t my daily so I can have it out of commission for a couple of days if I get stuck.

Thank you for all the great advice