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Reverse light wiring info for those who need help

bigmanjbmopar

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I was fixing my 69.....changing rear 68 bumper that previous owner had pu on to the correct 69. Now I needed back up lamps which I was able to get, seeing all wiring in place the lamps didn't seem to work so after figuring it out I decide to post in detail how it works so if some one in the future needs help here ya go :)



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.
 

4spd69RR

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So what you are saying the NSS is a stand alone cable that runs from the reverse switch on the trans to the starter relay correct.
 

bigmanjbmopar

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4spd69RR said:
So what you are saying the NSS is a stand alone cable that runs from the reverse switch on the trans to the starter relay correct.

Yes a ground wire from the center pin on the NSS goes to a push on connector(part of the 3 wire harness from the switch to the fire wall) on the starter relay. When the switch sees that the shifter is in gear it cuts off the ground that the starter relay needs to send voltage to the starter.

Basically all done by the levers inside the trans that engage the switch. If you can start your car in gear then either the switch is bad or you have the wrong lever set in the trans, I believe I have read some were that some people have ended up with 68 trans and put a 3 pin switch in only to find out it still would not work since the 68 did not back up lights the switch is only 1 pin I guess.
 

4spd69RR

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Do you have pictures of this cable, for some reason I was thinking it was included with the Battery harnes cables. I have to replace all of my engine bay harnesses because the original harness were worn out.
 

bigmanjbmopar

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I can take some, it runs from the firewall connector down with the speedo cable to the trans.
 

bigmanjbmopar

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IMAG0689.jpg

This is at the firewall connector 3 wires in one harness by them selves down to trans
 
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