Neutral Safety Switch - Reverse Lights on in R, D, 2, and 1

[digi_d]

Hey all, hoping for a little guidance or ideas here on my 69 Super Bee with a 727. Problem is as described in the thread title - here's some additional detail:
-Car has 40K miles on it, I'm the second owner and have solid knowledge about what's been previously done
-NSS & transmission internals are original
-I finished rewiring the car last month (engine harness, dash, and forward. Rear harness comes in next week)
-This issue popped up after rewiring
-Car starts in P & N and (as expected) will not start in R, D, 2, or 1
-Shift linkage is a bit sloppy, all positions work as expected except shifting from shifting from N to D keeps the car in N. I have to go down to 1 then back up to D to engage D
-Reverse lights do not turn on in P or N

From what I can tell in previous posts culprits are typically rooster comb, the NSS, or shift linkage adjustment. Please correct me if wrong but...
-If the linkage was out, wouldn't I be unable to select the correct gear and/or have starting issues?
-If the NSS was bad, wouldn't it give me no reverse lights at all or reverse lights on in all gear selections?
-Given the car has it's original rooster comb and NSS, I can't see it being a length or parts mismatch issue

At a bit of a loss here for further troubleshooting - any other input is welcome!

 

[Rishi]

I would test the switch. Eliminate all issue with wiring, disconnect the harness from the switch, and confirm the switch works correctly for each gear selected. Those outer pins will connect only when in R. The inner pin is only grounded when in P and N.

While you acknowledge the wiring has recently been fiddled with, and that may very well be where the problem lies, in the past, I've gotten myself all spun out on a wiring issue like this, because I failed to confirm the things like the switch were in proper working order.

 

[Lefty71]

Those outer pins will connect only when in R. The

Right....so unplugging the switch will rule out the trans and switch pretty quickly if the light doesnt go out.

 

[digi_d]

Thanks for the input guys, I’m taking a look at it presently. Interestingly, when I pulled the plug off the switch, the boot was full ATF.

 

[Rishi]

Good call on specifically testing the switch, I think that’s it. The two outside pins have continuity in R, D, 2, 1 but not in park or neutral. I’m understanding the wiring diagram correctly, those pins should only have continuity in R.

from memory, the center pin grounds in R to complete the backup lights circuit.

 

[digi_d]

Well the three new switches I bought all behave the same as the one that came out.

Put a scope in and I think it is indeed a rooster comb problem. Looks like I have the middle one in this picture:

If I’m understanding correctly, this would not work with a 3 prong NSS. I’m a little boggled about why it’s even in there.

Decided to cross check the serial and sure enough, 2801543 is a 67-68 code.

So now to figure out if I can just swap out the rooster comb over to the later style.

 

[GASSR]

So I have a question. I see a different switch listed for 68 - 77. It is the longer body one below. The one on the right in the picture seems to be listed for 77 and up. Do they operate differently or is it just a difference in size?

 

[digi_d]

Just closing the loop here after chatting with a few local transmission shops as well as Cope Racing Transmissions. The mechanic's consensus is to buy a new valve body and install that. Doubly so because I have a 69 Bee with a 68 transmission and the 68 valve body doesn't support partial throttle kickdown whereas the 69 does. Looks like it'll be this unit:
https://www.coperacingtrans.com/?product=727-904-pro-street-automatic-shift-valve-body-1969-up

Going to add a rebuild/refresh kit as well. From here, I need to make the decision around doing it myself (ugh) or having a local trusted shop do the work. I'm extremely curious to work on an automatic transmission but with limited space, resources, knowledge, and for piece of mind's sake, I'll probably have a professional do it.

So I have a question. I see a different switch listed for 68 - 77. It is the longer body one below. The one on the right in the picture seems to be listed for 77 and up. Do they operate differently or is it just a difference in size?

I'm certainly no authority but, from my research over the last couple weeks, with 3 prong switches you have 69-77 and 78-97. The functionality is the same but the dimensions are different. Also noticed that the 78-97 switches are recessed around the prongs:
https://www.coperacingtrans.com/?product_cat=nag1-parts

 

[ynst]

from memory, the center pin grounds in R to complete the backup lights circuit.

The center pin grounds the starter relay when in Park or Neutral.

The two outside pins switch the reverse lights on. Power in (IGN hot) on one pin and power out to the reverse lights on the other pin