A727 back up switch / neutral safety

[bigmanjbmopar]

Anyone have experience with the switch going bad? or your reverse lights not working due to the switch or wiring? If so what was the fix? I got strange readings from the volt meter at the starter relay and fire wall connectors.

69 has 3 wires going to the switch one is from the one side of the starter relay a neg and another getting pos from the radio connector and the third going to the back up lamps can't seem to get any volts out to the lamps but get it to the switch from the firewall but loose it suddenly once in reverse?
thanks

 

[bigmanjbmopar]

OK well almost too embarrassed to post this but it was just the fuse, guess I forgot that I had taken it out thinking well there is no radio so why do I need a fuse? well guess what that fuse doubles as the reverse lights too Back when I first got the car the wiring was all muffed up spent the first week repairing wires etc. fuses were blowing left and right and had to start from scratch.

Just in case some in the future needs help with trouble shooting their back up lamps here is a tip.

The main power comes from the fuse box to the radio connector, were it is tapped with the power for the back up lamps.

That line runs up and out to the fire wall connector were it is taken down to the neutral safety/ back up switch on the A727 trans. which is activated by shifting into reverse then the power is cross connected to the other side of the NSS(neutral safety switch) and sent back up to the firewall connector back into the cab and all the way out to the rear to the lamps. Which by the way have to be mounted in order to work the outer casing is used for grounding.

The NSS itself on a 69 has 3 pins on it unlike the 68 and earlier. the 3 pins are center pin is for the neutral safety which uses a ground/negative from the starter relay if the Shifter is in gear the switch cuts off the power to the starter thus the name NSS. the two other pins are for the back up lamps one is for power in and the other power out as described above.

Hope this helps some one out in the future.