Printer Friendly Forum Posts - 96 Grand Cherokee Dash problem

Thanks for looking at this!

`96 Grand Cherokee has no dash functions, everything that runs on the buss system is off line. The high beam indicator, blinkers, dash lights work, but the temp gauge, tack, gas, oil pressure, and speedo do not work.

I tryed to replace the dash cluster and the body controler located behind the drivers left knee and still the same thing.

Jeep was in a roll over and the guy said it was intermitent, then just went out totaly.

There isone fuse in the fuse panel slot 10, looks like it says "HBL SVCH" that has no power, and seems to be a direct ground.

what should a guy be looking for with these goofy things?

Any clue where I can get a wire harness diagram so I can try to see what feeds the signal to the body controler??

I never worked on one like this and any help would be great.

if it was in an accident the insurance should cover the repair.take it to jeep

the jeep was repaired two years ago, they won`t cover this repair.

I need to fix it, not pass the thing off to the next guy.

First thing is to get a copy of a wiring diagram to the instrument cluster. Make sure that every wire that is supposed to have power has power.

I likely have one if you can't find anywhere else. I would have to fax it to you though so I would need your fax #. I could also scan it and email if you give me your email address.

all the wires are acounted for going into the back of the cluster, but the two BUSS wires. I have power and keyed power and grounds going to the dash. Everything but the BUSS system works.

e-mail ncrukee@hotmail.com

ah, did you check continuity between the wires at the Instrument cluster and the body control module?

no I didn`t....

I tested all the wires going into the back [i]but[/i] the BUSS wires.

When the rest tested good, and the body computer is less then 1 foot away from the dash connector, those two wires I did not test for continuity between the body controler and the dash plug.

First thing in the morning.......

There is one fuse in the fuse panel slot 10, looks like it says "HBL SVCH" that has no power, and seems to be a direct ground.

I WORKED ON A CAR LIKE THIS 96 JEEP GRAND CHEROKEE A WHILE BACK. AND SAME THING HAPPEN.I FOUND A BAD FUSE CONNECTION THAT CONTROLS THE DASHBOARD GAUGES, DON'T REMEMBER THE EXACT FUSE, BUT IT WAS NOT MAKING A GOOD CONNECTION. WHENEVER YOU JIGGLE THE FUSE THE GAUGES WOULD WORK. i TOOK THE FUSE OUT AND CLEANED IT THEN PUT IT BACK AND EVERYTHING WORKED FINE. i DON'T HAVE THE DIAGRAM FOR THIS CAR, BUT I WILL LOOK AT AT WORK TOMORROW. I'LL POST THE FUSE NUMBER.

A wiring diagram would be awesome!

Then I could see what feeds what to where....so to say. :)

I had about 60% of the fuse box apart, it`s a sandwitch design made out of (what else?) plastic layers and layers of copper looking strips running here and there, and poking tabs out the top. About 6 layers of copper strips and plastic layer between each.

The fuses actually plugs into a extender that plugs onto a peg sticking out of the top layer of plastic and extent the connection up tp the bottom of the fuse panel cover. There are like 30 of these little suckers!!

I took them all off and looked for a corroided connection, nothing found, put them all back (I`m sure not in the same order) and it still don`t work.

Does the engine controler feed the signal to the body controler???

POst your email address and I will try to send you a wiring diagram.

Quote: Originally posted by PLAYER69 on January 28, 2003

POst your email address and I will try to send you a wiring diagram.

ncrukee@hotmail.com

I'll get it to you a little later today. What do you want a wiring diagram of? Instrument cluster and power distribution?

and where the signal for the dash cluster comes from.

The whole thing would be sweet!

You know if you just send part of it, I`ll need the part you didn`t send!! ;)

Well its not really as simple as just sending the whole thing. You would pretty much need to buy the service manual if you want the whole thing. I'll send all that I can find relevent.

This isn't as easy as I thought. In my service manual there is quite a lengthy procedure for diagnosing the instrument cluster. The bad part is that it requires a scan tool. Do you have a scan tool? The wiring diagrams are very limited and would be of very little help to you.

The next problem is that this book is just to damn big to copy. It is about 10'thick and makes it hard to photocopy into the creases. I will definately need to fax to you as you won't be able to read if well if I scan it. Like I said though I don't think this is going to be any good to you without a scan tool.

Where are you located?

Just to confirm I have now read the whole thing and you NEED a scan tool to diagnose this.

Here are the relevent wires at the IC.

Ground - BLACK/ Orange Z2 and Black Z1

Hot all the time - Violet F75

Hot in run and start - Blk/wht F87

CCD BUS + - Vio/Brn D1

CCD BUS - - Wht/Blk D2

These bus wires go to the Powertrain control module (Right side rear corner of engine compartment), Body Control Module (lower left of Instrument panel) and Airbag conrtol module (module below center console)

scan tool?

I have a Snap-On MT2500 diagnostics scanner if that`s what you meen.

or are you talking multimeter?

That is exactly what you need :) Do you have a the 1996 jeep cartridge for it?

I have the "Fast track Troubleshooter" card for GM-CHRY-FORD-JEEP thru 95 pt#MT25002995

and the "Primar yCartrage" for GM-CHRY-FORD-JEEP Domestic combination thru 97 pt#25001097

I run a scan and no codes found.

I run the CCD test...and:

Modules responding: -->Body computer

That`s all it says.

I can run the motor with the scan tool attached and it will read the info thru the scan tool including mph, rpm`s, temp ect.

Quote: Originally posted by PLAYER69 on January 29, 2003

Just to confirm I have now read the whole thing and you NEED a scan tool to diagnose this.

Here are the relevent wires at the IC.

Ground - BLACK/ Orange Z2 and Black Z1

Hot all the time - Violet F75

Hot in run and start - Blk/wht F87

CCD BUS + - Vio/Brn D1

CCD BUS - - Wht/Blk D2

I have no power at the Blk\wht wire...

where does that come from?? can I hot wire that to a keyed power supply??

I have continuity between both the BUSS wires and modules.

jumping that wire at the back of the body controler with both the old dash and body controler and the used ones I picked up both don`t work. :(

I don't know what more to say. If you post your fax # I can send you a flow chart to use with your scanner but I don't think it will help much. Do you know if it is the PCM or BCM that controls the IC? Perhaps you were changing the wrong one?

I had thought it was the body controler, but I`m not sure.

I changed the three plug unit under the dash just behind the drivers left knee and the dash cluster asmbly.

Isn`t the fact my scanner can only see the body controler key???

Isn`t the fact my scanner can only see the body controler key???

Sorry you lost me there. Please explain better. Post your fax # and I will send you the flow chart. It might help. Can't hurt!

when I use the scanner and scan the CCD system, it shows a few *****`s and when it`s done scanning says:

Modules responding: -->Body computer

That`s all it says.

I can run the motor with the scan tool attached and it will read the info thru the scan tool including mph, rpm`s, temp ect.

I don`t have a FAX machine. :(

ok I will scan it and email it to you when I have time.

I should have time today to do this.

Today I pull it in, the dash doesn`t work, I plug in the scanner, let it scan the system, it see`s the body controler, I click 'yes' and the system comes back on line! Now it`s working....what the heck?

This was the guys complaint, that it would come and go, now at least it`s working, maybe I can start tugging and pulling on wiring harnesses and tapping on moduls to see it I can find the problem.

I did find a not so good book on it and it does say that the scanner uses the BUSS system so if I saw everything working on the scanner, that should meen that the engin controler and the BUSS system to the scanner connector was good, so if I replaced the body controler and IC, does that meen I should be looking at the air bag controler??

Air bag controller no. It will only be receiving data, not controlling data. Possibly the power train control module though. From my understanding you have only replaced the body control module?

well, it`s not the modual under the center councel, I can unplug it and the dash still works.

Hasn`t gone off-line yet, still looking for problem.

Quote: Originally posted by PLAYER69 on February 03, 2003

Air bag controller no. It will only be receiving data, not controlling data. Possibly the power train control module though. From my understanding you have only replaced the body control module?

the body control module and the IC was replaced.n I was told that they have to be matching to keep the milage right or something.

and while it(the IC) was not working, I COULD read the data with the scann tool.

Well, it`s back! :(
It was great untill, they claim, it rains or snows, or they go thru the car wash. I hosed the whole under hood area this morning with a spray\mist bottle and tugged on all the harnesses with out getting the dash to fail at all. Does the fact it seems to be water related help at all?

Well, I splashed through a couple puddles and got it to fail. I have it in the garage now and the dash will constantly turn on and off. resetting everytime it does. The compass in the overhead resets with the dash. I have the dash out, and the compass down and there is a constant 12v + and ground at both the dash connector and the compass connector. I see no reason for it to be constantly turning on and off. The compass will reset with the dash unplugged. Is there a relay that controls both??
Or any ideas at all??

This is strange!
The cycling of the dash and compass is also tied to the door chime, when the dash resets the door chime starts over.
I can unplug evey single fuse and relay in both the fuse box inside the right kick pannel and the fuse box under the hood and the dash still continues to turn on and off. I can unplug the engine controler with the same results. When the dash goes out, my snap on scanner still sees all the info with no interuption. I can see nothing in the scanner that appears to be switching with the cycle of the dash. The compass does not go off every time the dash does, but the dash does go off every time the compass does. Sometimes it seems if I turn off the key the dash will stay lit up longer then it should, maybe 2 secs after the key is off before the lights go out, but the motor does shut off with the key.
Is there anyway to test the BUSS system as I have 12v keyed and aways on power with ground to the back of the dash, it almost has to be the BUSS system, doesn`t it??
The two BUSS wires also go up to the compass as well. I seem to have continuity between all the BUSS wires.

Found it!!
Orange wire going to the body controler is suppost to have keyed on and start power, it had neather. I tryed to pull the body modual`s black plug apart (wrong move) and it fell apart. I got one out of a salvage yard and before I soldered the connections I dissconnected one wire at a time till I found the orange wire made it stop cycling on and off. I got a factory wiring harness chart and found the orange wire was the keyed on and start wire from the under hood fuse box. I ran a new wire from the body modual to the under hood fuse box right to the back of the fuse it was suppose to go to, and now it works perfect, no more dash going out when spashing thru the puddles or going thru the car wash! :p
Thanks to all who responded and just make a mental note in case you run into a Grand Cherokee that loses the dash funtion when it gets wet.