Back Up Lights - Neutral Start Switch

Interior and Electrical

  1. Bruceynz

    Bruceynz Well-Known Member

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    Hi Guys,

    TF 904

    Ok my back up lights on my Cordoba don't work, there is a new 3 pin neutral start switch fitted when trans rebuilt, I put my meter on the 2 outside switch pins and I can't measure any circuit when putting in and out of reverse.

    The neutral start part seems to work fine.

    Are there different types of 3 pin switches?

    Thanks
    Bruce

    cu.PNG



    IMG_20200109_211129.jpg
     
    Last edited: Jan 9, 2020
  2. volare 77

    volare 77 Well-Known Member

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    I had defective China made switches right out of the box. I would use with a mopar one 2932820 if possible.
     
  3. Bruceynz

    Bruceynz Well-Known Member

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    does the switch have to be screwed in tight, or does it need half a turn out of something crazy?
     
  4. Aspen500

    Aspen500 Well-Known Member

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    I replaced my switch when building the car and it lasted maybe 6 months before I couldn't start the car (fortunately in my own driveway). Replaced it again and not long after, the B/U lights quit working. Not sure but I imagine both were "top quality" Made in China crap. Over at my dad's house about that time and we were talking cars (no big surprise!) when I mentioned the switch. He said there were 3 or 4 old ones from who knows where (original Mopar) in a jar in the basement. Screwed that one in and it's been good ever since. Moral of the story, China builds junk in a majority of cases.
     
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  5. Aspen500

    Aspen500 Well-Known Member

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    I replaced my switch when building the car and it lasted maybe 6 months before I couldn't start the car (fortunately in my own driveway). Replaced it again and not long after, the B/U lights quit working. Not sure but I imagine both were "top quality" Made in China crap. Over at my dad's house about that time and we were talking cars (no big surprise!) when I mentioned the switch. He said there were 3 or 4 old ones from who knows where (original Mopar) in a jar in the basement. Screwed that one in and it's been good ever since. Moral of the story, China builds junk in a majority of cases.

    It should be screwed in all the way, snug but not overly snug.
     
  6. Bruceynz

    Bruceynz Well-Known Member

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    Ok this is my old switch I pulled out a few years ago that I found and it doesn't appear to work either.

     
  7. Bruceynz

    Bruceynz Well-Known Member

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    I got under the car and shorted the 2 outside pins together and the back up lights turn on, so its a switch fault for sure!
     
  8. Bruceynz

    Bruceynz Well-Known Member

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    can anyone help me out with a a good switch?
     
  9. Aspen500

    Aspen500 Well-Known Member

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  10. BudW

    BudW Moderator Staff Member

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    When looking for a neutral safety switch, a couple of things to keep in mind. For automatics, Chrysler used a 3-pin switch. Older manuals used a 2-pin switch and newer manuals also use a 3-pin switch - which looks like the ones below (somewhat) but will not work for you.
    They all look identical when it is plugged into the wiring harness (other than automatics vs. manuals difference).

    For both versions, they made a long and a short version:
    NSS Long NS11.jpg

    NSS Short NS240.jpg
    Both versions of the (automatic transmission) 3-pin switch will interchange.

    Personally, I would not have any problem reusing a used switch – but would replace the odd shaped seal, first.

    Chrysler, Standard and another company (can’t remember the name) made new switches in North America – any of which are fine. A couple of decades later, the other two companies started to make them in China and those are iuYINYAKFP.jpg (not worth using, except in a pinch).

    If you find a switch that appears to be missing a pin – don’t use it. Those pins can break off especially if dropped or handled roughly.
    BudW
     
  11. Bruceynz

    Bruceynz Well-Known Member

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    ok my car has the long one at top in the picture in it now the short one my plug will not plug on to, the pins are different diameter as well and it can't go over the black plastic the diameter is to large.
     
  12. BudW

    BudW Moderator Staff Member

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    The pigtail is the same from ’68 to around 2000.
    Was the neutral safety switch you got for an automatic or manual transmission?
    BudW
     
  13. Bruceynz

    Bruceynz Well-Known Member

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    Well looking through my emails it looks like I bought this part number REPD506401 off ebay in 2016 for a torqueflite but when I search for it on google it says its for a "1980 International Scout II" :confused:
     
  14. BudW

    BudW Moderator Staff Member

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    Many Internationals and Jeeps (before Chrysler acquired Jeep) came with A727’s, but with a different engine bolt pattern and different propeller shaft attachment.
    I don’t know about the neutral safety switches International or Jeep used, though.
    BudW
     
  15. Bruceynz

    Bruceynz Well-Known Member

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    Description: NEUTRAL SAFETY SWITCH
    Pin type; 3-prong male terminal; A high quality, OE replacement neutral safety switch; Backed by 1-year, unlimited-mileage warranty.
    Fits:
    1974 Plymouth Barracuda

    1973 Plymouth Barracuda
    See more applications
    Fit Notes: AUTOMATIC TRANSMISSION
    Brand: Replacement
    Part Number: REPD506401
     
  16. Aspen500

    Aspen500 Well-Known Member

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    Not sure on the years but 1970's for sure, AMC used the TF with a different bolt pattern also and use the exact same backup/neutral switch as well as International and Jeep. I got curious and did some digging.:) No idea and makes no difference really but, Jensen Interceptor probably used the same one also since they had a TF727 behind the Mopar big block's under the hood.
     
  17. BudW

    BudW Moderator Staff Member

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    One website I pulled up showed part number REPD506401 does show to be an “American Motors only” part. Another site shows for Chrysler products only. I don't know enough about AMC to know for certain, but I doubt the websites would lie.

    I have replaced neutral safety switches both directions (install short in place of long and vice versa) many a time (over a hundred) – because Chrysler quit making the long switch and all replacements came were the short version. Not sure when the change was made (’79 or ‘80 – maybe).

    With that said, I have seen the pigtail connector shrink over time and fall off (and can’t get back on) when driving or it gets so hard it is impossible to work with. I have replaced a couple dozen of the pigtails back in the ‘80’s (a pretty quick job – if car is on a rack) because of what I mentioned or from it getting damaged (run over a stick or whatever). Most of the factory NSS switches gave very little trouble – but a few did.
    I have also damaged a few NSS switches when they were still attached to the transmission (rolling transmission over and breaking pins off, dropping a transmission, and so forth).
    Give your rubber pigtail a squeeze. You should be able to squeeze it to about 2/3rds the original size. If it doesn't, you might need to pickup a new connector. Several companies still make 'em.
    BudW
     
  18. Bruceynz

    Bruceynz Well-Known Member

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    My plugs is hard as a rock!
     
  19. Aspen500

    Aspen500 Well-Known Member

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    Replacements plugs are readily available.
    More Information for ACDELCO PT2139


    I just saw that AMC and Chrysler had the same aftermarket p/n's, at least for the couple years I checked anyways.

    transpurple100.png
     
  20. BudW

    BudW Moderator Staff Member

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    @Aspen500 I can't make out your attachment (a picture?).
    BudW