xj661

I have an 87 XJ 4.0 4x4 automagic. the CPS harness got a little rusty/crusty and after replacing the connector it's been working great ever since.
before the CPS caused the engine to stall the torque converter stopped locking up on its own.
I wired in a switch to lock it up to confirm the TC still works but the TCM isn't locking it up like it used to.

More recently the power/comfort switch went out and I replaced it with an aftermarket 3 pin w/led like the original but now the reverse lights aren't working.
I suspect the 2 symptoms might be related but I'm not sure where to check first. any input is appreciated

lawsoncl

The t/c lockup and the reverse lights could both be caused by the NSS. https://bleepinjeep.com/?s=NSS has some good videos.

On the older Renix Cherokees, there is a separate switch on the brake pedal for the TCM. If that's knocked loose or out of adjustment, the TCM will think you've got the brake applied and unlock the t/c. It's higher up than the normal brake light switch, and also has a vac line attach if you have cruise control.

Check the fuse marked "trans" for the reverse lights (yeah, doesn't make sense to me either, but that feeds the power to the NSS). The fuse for the TCM itself is wrapped up in the harness near the TCM, along with a pull-up resistor for the brake switch.

cruiser54

http://cruiser54.com/?p=58

http://cruiser54.com/?p=435

lawsoncl

The switch for the trans computer is the white one above the brake light switch

cruiser54

I LOVE that photo!! LOL.

xj661

I want to thank everyone for the info. my pedal was not hitting the switch. before getting it adjusted i took apart the switch thinking the pedal was adjustable and i lost the sleeve to the switch. im having a hell of a time finding one online and these jeeps get raided pretty quickly at the junk yards.

lawsoncl

You're still referring to the white switch for the tcu, right? PN is 56002281 for the switch and J4006789 for the retainer/nut. Discontinued of course. Also used in the wranglers at the time as well. As I recall the switch stem was threaded, so you might be able to find thin nuts that will work. You can buy generic brake switches with threaded nuts too that might be the same size, although that won't have the vacuum part if you need that for the cruise. Initially when I did my manual->auto conversion, I wired in a relay off the regular brake switch to ground the wire from the tcu when the brakes were applied.

Not sure on dimensions, but this looks like a possibility.
https://www.dormanproducts.com/p-23714-13808.aspx

lawsoncl

FYI, check this thread
https://comancheclub.com/topic/68043...itch/#comments
Mentions using p/n SL186 to replace both the trans switch and the regular brake light. (no vac connection though)

The switch itself is a SLS234.

xj661

that SL186 switch is exactly what im looking for. im gonna swap out the SLS234 switch with the 186 and repin it. finding that sleeve is gonna be a pain so im gonna get a bigger bolt and some washers to get the pedal stiff again. thank you so much for pointing me to that thread this saves me a bunch of time and frustration.