JKOwners Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
1,503 Posts
Discussion Starter #1
Anyone know how the neutral safety switch works in the JK? I have the console off and have checked all of the wires any where around the shifter, but can't find any that react differently regardless of on-off or park-reverse. Anybody out there have any ideas? I'd like to get my console back on.
 

·
Registered
Joined
·
1,186 Posts
No idea. Could its state be transmitted through the can-bus? Also did you check the wiring schematics?
 

·
Registered
Joined
·
494 Posts
I think its coming from the transmission range sensor mounted right on the transmission. Look for a light green 10 pole connector on the drivers side of the transmission. The T41 wire (Yellow with a dark blue stripe) is labeled P/N on the wiring diagram. I think it grounds when in park or neutral. The other end of the wire goes to the powertrain control module pin 27 on connector 4. The powertrain control module is the one directly behind the windshield washer reservoir. C4 is the connector closest to the engine. Since the TRS feeds the powertrain control module directly, you can't just add a relay and expect everything to be all warm and fuzzy. You'll need some kind of high impedence interface to connect to it to prevent pulling the signal to ground inadvertantly. If you don't understand what I just said, its best not to mess with it till you do. However, it it makes perfect sense, have at it. But verify that is good information first. All info came from the factory service manual for a 2008 JK. I have not yet personally verified it.
 

·
Registered
Joined
·
1,503 Posts
Discussion Starter #4
Nothin' wrong with warm and fuzzy. When you can get it. This makes sense, but also looks like it's falling way into the minus side of diminishing returns. As in a lot more can go wrong with this fix than right. Maybe another possibility: is there a circuit that's closed only when the vehicle is off?
 

·
Registered
Joined
·
1,503 Posts
Discussion Starter #6
what is the goal you are trying to get?
I have an electric shift on my transfer case and am trying to set up a neutral safety system so it can only be thrown in or out of low planetary when in park or neutral. Also only shifting with the JK turned off would be okay too.
 

·
Registered
Joined
·
494 Posts
Maybe another possibility: is there a circuit that's closed only when the vehicle is off?
You could power your own relay off the run relay circuit and use the normally closed contacts.
 

·
Registered
Joined
·
1,503 Posts
Discussion Starter #8 (Edited)
You could power your own relay off the run relay circuit and use the normally closed contacts.
What's the run relay circuit? Actually, don't I just need a switched source for the relay and an unswitched for the shifter and hook that to 87a instead of 87? Then when the switched source is off it closes the 87a circuit allowing the shifter to work. Right?
 

·
Registered
Joined
·
494 Posts
What's the run relay circuit? Actually, don't I just need a switched source for the relay and an unswitched for the shifter and hook that to 87a instead of 87? Then when the switched source is off it closes the 87a circuit allowing the shifter to work. Right?
The run relay is energized when the vehicle is running to power things like the radio, windows, wipers etc. The 87a contact is not currently used for anything that I can see so it would be available IF you can get to it. The run relay is located in the TIPM (main fuse module). If you can get to the bottom of the TIPM (good chance of it) just add a the proper connector to utilize 87a. I would still add a manual switch for the shifter to turn off power when you're not in the vehicle.

Have you thought of installing your own neutral switch on the gear shift?
 

·
Registered
Joined
·
1,503 Posts
Discussion Starter #10
Sorry, I meant the 87a on the relay I would install.
 

·
Registered
Joined
·
494 Posts
Yeah, thats what I thought, but I figured you may be able to save a few bucks by running it right off the run relay if possible. There's lots of places to pick up the run relay signal for your own relay if you go the other route.
 

·
Registered
Joined
·
1,503 Posts
Discussion Starter #12
Thanks, I was thinkin' way too hard in one direction on this one. It's great to have someone to get ideas and bounce some others off of. It works now. Much appreciated.
:beer:
 
1 - 12 of 12 Posts
Top