Not Starting Park Selector

[XRT38]

I have a 1990 Comanche with an automatic that isn't starting. The truck has a selector bar on the steering column like a normal automatic in a car and not a tunnel mounted selector like Cherokee's with automatics have.

 

The issue is the park selector on the column.  It's been an on-going issue where you turn the key and nothing, but wriggling the selector a bit usually causes it to make contact and start. So obviously there's a mechanical connection that has to be made for the truck to start when it's in park and so where is that?

 

I don't know is where that contact is:  What moves, and to where, in order to make contact to allow the truck to start?

Is it this little metal rod that is shown in this link that moves when you move the selector to park?

 

Thanks in advance for any input.

 

[Minuit]

You'll need to clean the neutral safety switch on the side of the transmission. One of its jobs is to prevent the truck from being started unless the truck is in park or neutral. Over time, the electrical  contacts in the switch get dirty and make intermittent contact. If you can get it off the transmission without breaking it, it can be disassembled and cleaned.

 

http://gojeep.willyshotrod.com/HowtoNSSrebuild.htm

[jpnjake]

Your adjustment on your cable could be off too, go under the truck and see if you can push the selector manually into park, then if you can follow the cable up and try and adjust it to take out the slack 

[XRT38]

Thank you for the timely responses and links. I'm sure this is the issue and fixing this is something I can do. 

I'll report back when the mission is accomplished but I am confident that this is the issue. Thank you for the

direction.

[XRT38]

Follow up on this topic. 

First off I was confident that the recommended repair would likely solve the problem. This was reinforced by understanding that the back up lights which had just recently stopped working were directly related. All evidence indicated the NSS was the culprit.

 

I managed to remove the NSS with only minor complications. This was primarily thanks to the built in drive train auto lubrication system, which is an advanced feature of self loosening valve cover bolts.  Consequently the entire transmission has a fine rust preventive oil coating and that enabled the NSS to be gently, very gently, pulled outwards with a slight side to side wriggling on it.

 

The biggest problem are the Zip Ties that attach the cable to another cable deep inside the transmission tunnel and up high where you have almost zero working room. How anyone manages to cut those without damaging the cable with cutters is beyond me. 

 

The Zip Ties on the wiring cable can be almost impossible to remove, but the trick to these is get a soldering iron and then melt those in half, which is how I rather quickly removed that impediment to success.

 

The outer large wiper bolt was loose, and the lock tabs that supposedly secure it were bent outwards and one was twisted. They were not engaging the wiper arm nut much. Quite frankly I'm surprised mine was still attached.  This meant that the wiper arm inside of the NSS wasn't being pulled against the contacts inside. There was almost no tension being put on the wiper arm.

 

Opening the NSS and cleaning.

 

Next, when I removed and opened the NSS there was no noticeable spring action on the wiper arms teeny tiny copper wipers.  The grease inside was hard and glue like. The tiny springs were so gummed up they weren't providing any noticeable spring action to the wiper contacts.

 

* Caution here for any future readers: The springs that push on the wiper arm's contacts are extremely small.  Remove the NSS and put it on a table or area which is clear and clean so that you do not lose the springs. Work slowly and carefully when removing those tiny copper contacts that the springs reside under. If disaster should happen and you somehow lose a spring you could improvise with a cut down spring robbed from a disposable lighter.

 

I bought the recommeded CRC electrical contact cleaner and some dielectric light bulb grease and then cleaned and relubricated the inside of the NSS. This restored the spring action to the wiper contacts and then reassembled the NSS for reinstallation.

 

Patience is needed because it looked to me like the shaft coming out of the transmission that controls the NSS is plastic. You do not want to break that obviously. I might be wrong and it may be metal but mine looked like it was plastic. 

 

Long story short, after a number of times monkeying around with the NSS's position I finally managed to get the wiper arm shaft aligned with it's hole along with the top bolt hole.  The top bolt that secures the NSS to the transmission seemed to be stripping so I stopped putting torque on the bolt.  Just be careful you don't strip it is what I'm saying. It's only an aluminum thread that the bolt goes in to. Possibly vibration over a half million miles made this marginal. 

 

Once everything was reconnected I then put the selector in reverse as directed and turned the key to on and checked the rear back up lights.  Next, I then placed the drive selector to park and started the engine. I then shut it off, restarted in neutral, shut it off, and then tried to start it in drive and the low ranges which it did not do.  I deemed the repair a complete success and went inside to file this report.

 

My deep thanks to the Comanche Club for the help.