Reverse lights not working

[noreastfish]

I had a transmission shop reseal my 727 transmission.  I'm not positive if these is related or not but I do know they were working group before the car went into the shop.  I've checked all of the wiring and jumped the plug and the reverse lights come on. Power goes to the black harness side of the switch when in reverse but it doesn't go over to the reverse light wire on the plug. The car starts in park and neutral.  And it doesn't start in reverse, drive and low gears like it is so posed to do. All I can think of is there is something  inside the transmission that's not triggering the switch to power the reverse lights.  Any help would be greatly appreciated. 

[Katfish]

Did they change the NSS?
Some are more finicky than others.
My car wouldn't start in part or neutral and the reverse lights didn't work.
Changed NSS switch and reverse lights now work, still doesn't start in park though.
There's been several threads on different NSS switches.

[noreastfish]

I'm on my 2nd NNS and replaced the switch plug also.
Just not sure where to test next. I know inside the transmission it grounds the center wire to the starter solenoid so the car starts. I'm wondering if somehow something inside the transmission causes the NNS to jump the current to the reverse light wire.

[Cuda Cody]

Rooster Comb (normally that makes it come on all the time)?  Ground?

[noreastfish]

It does have power on the black wire of the time. If I jump the black wire to the other outside wire the reverse lights will come on. As soon as I plug it back in the lights don't work. Driving me crazy. I just ordered another plug but honestly I'm just grasping at straws now. I tested the switch according to the service manual and it tests fine.

[71383bee]

It sounds like the comb and plunger of the NSS are not making correct contact when in reverse. Sometimes tightening or loosening the NSS can get it to contact the comb better.

For whatever reason NSS's have become a real pain! 


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[7212Mopar]

If the NSS pin cannot fully extend, no reverse light. My fix was to enlarge the indentation of the plastic sleeve at the rooster comb using a Dremal bit. You can test it before putting trans pan back on.

[noreastfish]

Thank you everyone for your responses. I kind of did the same thing as 7212Mopar but I used O rings to space the NSS out far enough so the reverse lights work while still being able to make contact  with the center please wire so the car will start in neutral and park. I basically just kept turning the switch about a quarter of a turn until I found the happy spot so everything was working. I then marked the switch to the transmission case. Counted the turns to remove the switch installed a O  ring then installed  the switch making sure it was in the previous  location. Started the car and checked for leaks. So far so good.