Programbo

I`m tracing down an electrical problem and noticed that right under the steering wheel area and up under that long piece that runs along the bottom of the dash there are 2 black plastic boxes with a lot of wires running into each which are like attached with velcro..The one I know is the Transmission Control Unit but the other just has wires going in one side of it but not out the other and inside there are slots for 5 or 6 relays..There are 2 relays in it and I`m wondering what they are for as everything seems covered by the fuse panel and the relays out under the hood

Long Island XJ

on a serious note. Do you have cruise control? If not then that is what that box should be for.

Programbo

I guess a photo might have helped but I figured anyone who might know the answer right off the top of their heads would know just from the location and description...But no I don`t have cruise control

Carl48

The trans control unit on my XJ is on the passenger side. Only have one box on the driver side (no cruise) and it is the wiper delay module.

Jamie57

Apparently the cruise control module was installed even if you didn't get cruise.
there is another thread in the forum with a picture of one. It was Chryslers way of saving money as cruise was sometimes added at the dealer.

thesundancekid

is there anything written on this second black box perhaps if it is an old alarm with remote start the old units used to have a black box then some of the wires were linked into a 5-6 pack relay if it was disabled on the remote start function it would still have 1-2 relays in it for the starter kill if the pack comes out to some thicker 12 gage wires with the colors pink,pink with white stripe, purple, black, 2 reds and orange and perhaps a green then its most likly to an old viper remote start any numbers or letters on this box would definatly help id what it is

Programbo

I went to the junkyard today and looked at a bunch of other Cherokees and discovered that no two had the same stuff under that strip that runs along under the dash..the one "black box" which I falsely assumed was the TCU was indeed for the wipers..The other with the red, blue and black relays in it I still have no idea what they do if anything...The TCU was as mentioned over on the passenger side and is a silver metal unit..I`ll still have to trace all those wires as the TPS, TCU and CTS all share a common black/blue ground wire and all of those things seem to play some part in the check engine light popping on so i`m thinking there is a bad ground that is common to all these things and lacking that they are all using the TPS as a ground point which is causing the problem

Carl48

The ground for these items appears to be in the PCM (computer) pin 4 "sensor ground".

rustfarmer

I too am curious about the relay block. Mine also has only two relays in it. I don't have cruise, and have manual windows and door locks.

fb97xj1

Wouldve been nice if the OP posted a pic, huh?

Is this it?

https://www.cherokeeforum.com/f2/fus...-inside-92850/

DFlintstone

Probably its for tracking you. Only Sarra Sanders could deney that for sure.

Steven Dittert

I think this is the relay bank being discussed. Does anyone know which is the wiper relay? I've been tracking front wiper problems and have so far replaced the wiper motor and replaced the intermittent "box" with a used one. I bought a wiper relay from PartsGeek, but can't find where it goes. I also have looked for the fuse, but the diagrams show a "slot 20" for the wiper fuse and my fuse panel does not have a slot 20! The good news is that I did get the slow speed wiper to work (no fast or intermittent), but when it rained (and my son was stuck at work) the wipers stopped working.

My project today is to replace the ignition switch because I read in another thread that it may be the culprit. Additionally, there is no evidence of water getting into the passenger compartment. Does anyone have any further ideas?

Thank you so much! New to the forum.
Steve