# Inhibitor Relay Switch Problem?



## zfreak31 (Aug 22, 2006)

I recently was under the hood of my 86 300zx turbo and noticed that on the passenger side next to the cruise control vacuum that the inhibitor relay switch was unhooked. I searched everywhere but cannot figure out where it connects. I know it sends the signal about what gear the transmission is in, but cannot find where this hooks up at. It's an automatic and without it hooked up it seems to shift into a lower gear under very little pressure from the gas pedal. at around 70 or 75 it wants to continuously try to shift into passing gear. I checked the kick down switch and it's nowhere close to the pedal. When I push the pedal to the floor it shifts down into passing gear (and sometimes lower shooting the rpm's way into the redline). any help would be greatly appreciated.


----------



## Madmaxfl (Oct 22, 2005)

There should be a connection that comes from the transmission that goes to a junction under the battery. Get under the car and look.


----------



## zfreak31 (Aug 22, 2006)

I put the car on a lift and looked under it. There's about 2 or 3 wiring harnesses coming out of the transmission and all appeared to be connected (real hard to see). Is it possible that this transmission has been swapped out for another and connected differently. I checked the relay that isn't hooked with a multimeter and it still appears to still be showing that it has continuity on the prongs that are supposed to have it when it's in park, but haven't checked it in other gears to see if the continuity will change to different prongs as the transmission changes from park to reverse, neutral, etc..

Thanks for the help.


----------



## Zen31ZR (Mar 24, 2004)

I hate to ask this question, but do you have the factory service manual? WOuld probably solve all your problems with searching. I created the FAQs up at the top of this section to help with finding various important things like that, you should give them a try........ The FSM link you might need is near the top of the 1st post.


----------



## zfreak31 (Aug 22, 2006)

Thanks Zen. I finally found the FSM and it didn't really show anything (didn''t have a lot of time to search through it though) but I'm gonna trace each harness coming off the tranny and I'll let you know what I find. I'm thinking maybe nissan added certain extra harnesses for the options of having different trannies in them.


----------



## mwolvin (May 21, 2004)

Check under the EL section of the FSM. I noticed there is wiring diagrams along with what the connector looks like, and where it is supposed to be located. You ought to be able to trace it that way fairly easily. It's towards the end of the section. Happy browsing (150+ pages)


----------



## zfreak31 (Aug 22, 2006)

I've got 2 words for myself, [email protected]#$. Thanks to everyone for everything. I went to the FSM where mwolvin said, I started looking at the wiring harnesses and finally found it.The only difference was that it is located differently. As I continued to look I finally found the the harness I've been referring to as the inhibitor, ( I have a Haynes manual that described it as the inhibitor. I don't think Haynes even know's what they are talking about. The harness they have a picture of, and were calling the inhibitor is the shock harness). Originally I had adjustable shocks on the car and because of the price I changed to regular gas shocks. I did this about 6 years ago and had forgotten that I even done it. Now of course it bites me in the rear. All I can do is apologize to all the time spent. This just goes to show that even the people that write these manuals don't have half the knowledge of the expert people in this forum.

#You know you've owned a car too long when you begin to forget the things you've already done to it.#


----------



## Zen31ZR (Mar 24, 2004)

Congrats on finding it. This still doesn't fix your intial problem, though.


----------



## zfreak31 (Aug 22, 2006)

Found it finally. It was a small vacuum leak on the hose running from the intake to the transmission modulator. Near the vacuum modulator there was a small leak and once I fixed it, the tranny started shifting right again. Just hope it didn't do any damage to the tranny though, but it seems to be running fine.


----------

