Backup lights issue

[Ryunker]

In the past two days I have focused on making this car drive, without law enforcement issues. Today at lunch, I successfully completed the turn signals along with brake lamps. So I have all of the lights good with exception of reverse lamps. Kind of a kick in the nuts as I repair cars for a living...

This car has one plug from the C6 NSS going up and connecting behind the left valve cover, NSS works fine as in the car will not start if it is not in park or neutral.

I have new bulbs in and they light when I apply power with a power probe in the trunk area. The harness that goes from the trunk back to the dash has only two 4pin connectors by the kick panel. I have reviewed the online wiring diagrams for 1971 posted on this wonderful site, but they do not match what is on the car.

Facts on hand,

1. The instrument cluster is not installed, have the tach plug jumped. 

2.There is three connectors coming down the steering column, one is not connected as I really do not know where it goes, like a four pin female flat one. I will get a photo of that one tomorrow.

3. This car has been in pieces close to two decades.

I am looking for direction as in where to physically find and trace power back to the reverse lights. On a good side, the wiring other than tape un-raveling, is un-molested every where I can see. So I am looking for direction to troubleshoot at the connectors as my goal is not to damage what may still be good.

 

[Don C]

I would start at the NSS, make sure you have power at the white/purple wire, in the connector, with the key on. If so, jumper from that wire to the black/pink wire and see if the backup lights work, if not, the problem is between the NSS and lights. If they do work, the problem is likely in the back up portion of the NSS. Check the continuity of the switch with the transmission in reverse. If the white/purple wire has no voltage with the ignition switch on, the problem is between the NSS and the fuse or the fuse feed.

 

[midlife]

Don C is on the money; I will only add that the fuse in question is at the top right.

There are two variants of tail-light connectors for 71: an early version that has a 4 pin plug white/blue and green/white wire in the red plug and another 4 pin plug (but only 3 usable pins) without those wires. That might explain the discrepancies you see with the wiring diagrams, as the early version is not shown.

 

[c9zx]

I had the same problem. I had to open the NSS, clean the contacts, re-lube, and reassemble the NSS. There is a post here somewhere. Search on neutral safety switch posted by c9zx. Chuck

 

[Ryunker]

I had the same problem. I had to open the NSS, clean the contacts, re-lube, and reassemble the NSS. There is a post here somewhere. Search on neutral safety switch posted by c9zx. Chuck

Yup, problem seems to be with the switch. I jumper the two wires as detailed above and the back up lights shine bright.

It will be like a week or two before I can tackle the internals of the switch, little brother passed away and the awake and funeral stuff starts tomorrow, followed up by a weekend getaway with my wife, leaving PITA teenage daughter with friends...

I feel much better knowing where the problem is, helps me sleep at night.

 

[c9zx]

So sorry to hear of the loss of your brother. Glad to hear you have the switch problem figured out. Chuck

 

[Vinnie]

Very sorry to read about your brother's passing. My condolences.