caffeine27
Active Member
1970 Plymouth GTX. 440 Automatic.
anyone know how to fix this?
anyone know how to fix this?
Reverse Light when in drive instead of reverse
- Thread starter caffeine27
- Start date
Mocajava
Well-Known Member
Does the light NOT come on in reverse?
bigmanjbmopar
Newb with a view
Bad switch at the trans or linkage inside needs adjustment, Is your NSS a 3 wire?
caffeine27
Active Member
Light comes on in drive. Is off in every other gear. Sorry I'm not a mechanic, what is a NSS?
HT413
Semi Pro Bowler
NSS is a Neutral Safety Switch, located on the transmission. With the 3 wire NSS, when the trans is in reverse, the switch completes the ground circuit to the reverse lights, turning them on. or, that's what is supposed to happen.
Just curious, did they always do that or is this a new development?
Just curious, did they always do that or is this a new development?
bigmanjbmopar
Newb with a view
Bet you have a reverse valve body in your trans? Do you know if the transmission was rebuilt and the specs? NSS what he said
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After 68 I think
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After 68 I think
HT413
Semi Pro Bowler
Nah, bigman, I meant his reverse lights - did they always do that or did he do something that caused it. Haha
caffeine27
Active Member
After my mechanic serviced the car this happened. I thought maybe he wired or has something plugged in wrong.
HT413
Semi Pro Bowler
Geez, I'm just trying to figure out how on earth this can happen. The NSS might be defective, but I've never heard of one suddenly changing from normally open to normally closed. Most times they just stay on or off. But either way, I'd start with changing out the NSS on the trans.
caffeine27
Active Member
You don't have or know of any documented procedure on this do you?
HT413
Semi Pro Bowler
It's really easy. I've attached a photo of a 727 - the arrow shows you where the NSS is. I've also attached a photo of the connector. All you have to do is pull it off, replace the NSS and plug it back in. You probably will have some tranny fluid drain out, so be prepared. Also, check the connections are clean. If they are fugly, just spray a little vinegar and salt mixture on them, wait like 30 seconds, then clean thoroughly, spray with some non conducting electrical lube (or slather some silicone based lube on) and pop the connector back on. Also, the new NSS should have an aluminum crush washer on it to help it seal - make sure the old one is removed before putting the new on one, or it might leak.
caffeine27
Active Member
Dam. Thanks a whole bunch. Lot's more questions to come.
Great forum and great people..
Great forum and great people..
747mopar
Well-Known Member
The middle terminal completes a ground for the neutral safety, the outer 2 are a switch for the reverse lights. Sure sounds like the switch is working just not when it's supposed to, you said it happened after being serviced.... what did you have done?
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caffeine27
Active Member
747 Mopar. The tranny fluid was changed and they checked it. It shifts fine.
747mopar
Well-Known Member
Just seams like something got knocked out of whack in the tranny? It's been too long since I looked in one to remember how easily this could happen.
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I know just beneath the case there's a cam if you want to call it that which activates the reverse and neutral safety, just can't remember how it's held in place?
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I know just beneath the case there's a cam if you want to call it that which activates the reverse and neutral safety, just can't remember how it's held in place?
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