NSS/Backup Switch Bench Test

[quagmire]

Ok just to make sure I haven't gone completely insane, in order to bench test the neutral safety switch one lead of an ohmmeter should be on the center pin and the other on the body of the switch.  Pushing the plastic switch portion should open and close the switch, right?  Mine went bad, and I have now tested two brand new switches that are acting the same way!  Am I missing something here?  The backup switch portions all test fine.

[Bullitt-]

Center pin to ground is correct...I'm just not sure which position should test closed..out or in, but one of them for sure.

[quagmire]

Ok then, I guess I'm not crazy!  I have two brand new switches that aren't even the same brand and they both aren't giving me continuity regardless of switch position.  I guess it's back to the parts store for round 3.......

[dodj]

The outside two prongs are isolated from ground and are the ones that provide the switching action for your reverse lights. You will read nothing from either of these prongs to ground regardless of switch position - unless your switch is shot and in the case you do read zero to ground you have probably blown fuse #8. If you put your ohmmeter leads on each of the outside two prongs and work the switch you will see the reading go between zero and infinite. I don't remember if it is zero when pushed or not - I think when it is not pushed in.
The centre prong is for completing the seat belt relay circuit (not a concern for a lot of people - like me)

[quagmire]

The outside prongs for the back up switch work fine, it's the center terminal which is the neutral safety switch.  It doesn't switch to ground at any position, and since it provides ground to the starter relay my car won't start unless I jumper it. 

[dodj]

and since it provides ground to the starter relay 

Ya, that to - sorry, forgot to follow out the rest of the cct before posting. Wouldn't be much of a NSS without that part.

[dodj]

If you are testing the grounding portion of the NSS (I misunderstood your question the first time I read it) you need to put your ohmmeter leads from the centre pin to the small steel button in the middle of the plastic plunger on the other side of the switch, not the body of the switch. The NSS pins are isolated from the body of the switch. Also NSS doesn't switch the ground, the internals of the tranny does so you don't need to operate the switch while testing

[Bullitt-]

If you are testing the grounding portion of the NSS (I misunderstood your question the first time I read it) you need to put your ohmmeter leads from the centre pin to the small steel button in the middle of the plastic plunger on the other side of the switch, not the body of the switch. The NSS pins are isolated from the body of the switch. Also NSS doesn't switch the ground, the internals of the tranny does so you don't need to operate the switch while testing

I don't understand how this could be so as the switch is activated by a plastic piece inside the tranny...  I quote "It is relatively common for the plastic wiper on the arm to loosen or break. When the plastic breaks the switch can't be activated."
  Reference page 67-68 http://books.google.com/books?id=IjnczMjW46QC&pg=PA67&lpg=PA67&dq=test+neutral+start+switch+chrysler&source=bl&ots=1nxuPBYlXK&sig=XrdWIQBvo0T_0U4VvJFIW_DZdXw&hl=en&ei=hIqnSo-IBc-OtgeKhqCcCA&sa=X&oi=book_result&ct=result&resnum=10#v=onepage&q=&f=false

[quagmire]

That's what I thought.....  The center switch opens and closes the backup switch pins when I toggle it.  And the rooster comb on the manual lever is plastic anyways.  I'm pretty sure it grounds through the switch body and trans case.  Problem is, neither of these new switches seem to do that at any time!

[tactransman]

If you are testing the grounding portion of the NSS (I misunderstood your question the first time I read it) you need to put your ohmmeter leads from the centre pin to the small steel button in the middle of the plastic plunger on the other side of the switch, not the body of the switch. The NSS pins are isolated from the body of the switch. Also NSS doesn't switch the ground, the internals of the tranny does so you don't need to operate the switch while testing

It grounds thru the trans only by touching the two metal sections on the VB part. The "low spot" in between activate the reverse part of the switch.

[quagmire]

Huh, that makes sense.  Kind of a goofy setup!  I'll have to retest when I get home.

[Bullitt-]

AHH I see said the Blind Man

[shadango]

The outside two prongs are isolated from ground and are the ones that provide the switching action for your reverse lights. You will read nothing from either of these prongs to ground regardless of switch position - unless your switch is shot and in the case you do read zero to ground you have probably blown fuse #8. If you put your ohmmeter leads on each of the outside two prongs and work the switch you will see the reading go between zero and infinite. I don't remember if it is zero when pushed or not - I think when it is not pushed in.
The centre prong is for completing the seat belt relay circuit (not a concern for a lot of people - like me)

What should happen if the shifter is in reverse and I do an ohms check between the two outside pins on the switch...it should read zero, right?

I get nothing....infinite...so I assumed that means its a bad switch....but now there is the INTERNAL piece mentioned?

[dodj]

What should happen if the shifter is in reverse and I do an ohms check between the two outside pins on the switch...it should read zero, right?

I get nothing....infinite...so I assumed that means its a bad switch....but now there is the INTERNAL piece mentioned?

Probably a bad switch. It fails more than the piece inside the tranny (I think). It should read zero or close to zero when you are in reverse. Bench test it after the tranny is out and if it tests ok, have the tranny shop check on the condition of that piece inside the tranny. I think Terry called it a vb. Of course, from the sounds of things in your transmission thread, the tranny shop you're using doesn't have an over abundance of torqueflight knowledge.
Shadango, I think you have used the "banging head on wall" smiley more than anybody else! Get the feeling this car is fighting every step to completion? Maybe it likes the garage more than the street.