727 Back-up Light Issue

[bad88ttop]

Hi guys,
I have a 70 Charger w/ a 440-727 combo. For some reason the back-up lights wont' work. When you bypass the starter sylenoid on the firewall and ground the brown wire w/ the yellow tracer, the back-up lights work. I also had someone stand behind the car as I went thru the gears and they never flash or blink. The harness is a brand new Bill Evans and I believe my jumping it and the lights working, it's not a wiring issue. That leads me to believe it's either a back-up light switch issue or something inside of the trans. Any ideas would be greatly appreciated. Thanks

 

[Dipstick]

The two outer sockets on the NSS connector are the BU lights, connect them together and turn the ign switch to RUN. If the lights come on the wiring is OK and the NSS is faulty or the internal plastic wiper is broken.

 

[bad88ttop]

The two outer sockets on the NSS connector are the BU lights, connect them together and turn the ign switch to RUN. If the lights come on the wiring is OK and the NSS is faulty or the internal plastic wiper is broken.

Tell me more about this "Plastic Wiper" in the transmission? If I remove the NSS can I see it thru the hole? Thx for the response.

 

[Dipstick]

Tell me more about this "Plastic Wiper" in the transmission? If I remove the NSS can I see it thru the hole? Thx for the response.

The '69-later shifter detent inside the transmission (often called a rooster comb) has a plastic wiper that operates the NSS, if it is damaged it could prevent the NSS from working properly. Yes, you can see it through the hole.

 

[bad88ttop]

The '69-later shifter detent inside the transmission (often called a rooster comb) has a plastic wiper that operates the NSS, if it is damaged it could prevent the NSS from working properly. Yes, you can see it through the hole.

View attachment 742006

Thanks man. You have me curious now what the hell is going on? Possibly I'll try the original switch...