1997 will not start. Wiring problems??

My 1997 Jeep Grand Cherokee just shut down on me. When I turn the ignition on, I notice that I no longer see the engine light and all of the gauges read 0. The voltage gauge reads 0 even though the accessories all work fine. I checked the fuse for the gauges and it was good. I can see the ABS and the air bag lights start up when I put the fuse back in. I assumed that the gauge cluster was working properly and that it was not receiving info from the PCM. I have also noticed that my overhead mileage display now reads "--". I decided to scan the PCM and found
that I can no longer read it. I purchased a used PCM from a junkyard and nothing changed. Now I'm thinking that I may have purchased a bad PCM. I then purchased a refurbished PCM from NAPA. I know that the new PCM needs to be programmed at the dealer but now that I have it installed, should I still be seeing the same problems? What else could cause this problem?

I have read about this faulty gauge cluster connector and have cleaned
the connectors and tested to verify the connection. Never the less, the
engine should still run w/o the gauges working.

[QUOTE=Thetzer]My 1997 Jeep Grand Cherokee just shut down on me.


i had same problem with no backup lights,and dash lights,gauges,etc!!!
under the dash on drivers side there wiggle the connections on the harnessconnections down there..on my jeep for the reverse lights i found the connector that was bad the female side of the harnesswas not makin good contact with the male side so i used a very thin pointy tool to bend the copper tabs on fem side(BE VERY CARFUL AND PATIENT)

BUT THE OTHER PROBLEMS ARE INTERMITANT...somtimes even no start,
other times just while driving i hit a bump and the spedo and tach just drop to zero and the alarm l.e.d comes on..all i do is move the harness under the dash with my foot and everything goes back to normal..

i will fix those the right way one of these days.. :) i hope this was helpful..

Good luck!!!!

I think that I have found my problem. I found on page 26 on this site. Believe it
or not, if the CPS shorts to ground, it could take down the PCM and the gauges. They
even indicated that the ENGINE light will not come on when I turn the key. I
have been reading about this for weeks and this one has all the same symptoms.
Funny but I purchased one used and one refurbished PCM and the part that seems to be
causing all of this trouble is one that I already have in the garage. Well, the
money is not the issue for me, I love my Jeep and will not replace it and I have
NEVER went to the dealer for repairs and I'm not about to start.

I think that I have found my problem. I found on page 26 on this site. Believe it
or not, if the CPS shorts to ground, it could take down the PCM and the gauges. They
even indicated that the ENGINE light will not come on when I turn the key. I
have been reading about this for weeks and this one has all the same symptoms.
Funny but I purchased one used and one refurbished PCM and the part that seems to be
causing all of this trouble is one that I already have in the garage. Well, the
money is not the issue for me, I love my Jeep and will not replace it and I have
NEVER went to the dealer for repairs and I'm not about to start.


Wel your right about that one. the problem with the CPS is the wiring tends to get fatigued where it enter the CPS base, and the wires will bare here and ground of of the other wires, hence your problem.

I had an issue for 3 days last winter where my jeep wouldn't start, I pulled it into the garage and started working on it, troubleshooting everything, I didn't think it was a bad CPS because my CHECK ENGINE light was coming on, so I start search for bad wires, I found my 8volt supply wire (for the CPS, Cam Sensor and VSS) was getting no voltage, so I checked for voltage at the PCM end of it and still got nothing. So I thought it was a bad PCM, a friend had an extra PCM for his 94 so I tried it got the same results. I cut the wire (8volt supply) and tested it at the PCM and got voltage back, hooked it back up and nothing, so now I knew this wire was bad somewhere, well I reached back and grabbed the wiring for the CPS and wiggled it, thinking that maybe the wiring for the CPS was touching my exhaust manifold or downpipe and causing the short. Well after that I hooked it up and still had juice so I thought that was the exact problem. Got eerything back together and she fired right up. I drove around for a few more months without fixing the CPS wire, then this past spring I decided I would remove the CPS and fix the wiring (that I thought got melted on the exhaust manifold) before it caused me more problem down the road. When I got the cps out I noticed that there would be no way for me to fix the wiring because the housing was broken right where it goes into the CPS (the wiring got fatigued and housing got stripped off). So I end up buying a new CPS to ensure not future problems.

There's my luck again... I have a new CPS and pluged it in w/o removing
the old one just to see if anything changes. NO!! I have the same
problem. I have inspected the wiring all the way back to the PCM
and all checks good. I coundn't wait to get home today to test it.
Now my mood has changed!!!

I do not have 8 volts needed at the CPS connector. It's time to find a more detailed wiring diagram for this vehicle. I must add that I have read a lot of messages regarding fuel pumps and it's nice to hear mine running every time I go out to work on it.

If the CPS shorts to ground, I can see it taking out the 8 volt supply. This same 8 volts is needed for the gauges and the vehicle information center and this is why I no longer see the engine light but if it shorts to Vcc or to the 8 volt side, it will not take down the 8 volt supply, it will simply stop the engine and the computer will send an error code.

Well if the 8 volt supply wire is gruonded any where along the way it will shut down power to the entire wire even from the PCM, the only way to test this would be to cut the 8 volt supply wire at the pcm (leaving enough room to repair it later) and check for 8 volts at the PCM end of the cut. You should hae 8 volts with the key in the ON position.

I would suggest before cutting any wires to get a detailed wiring diagram and make sure the powers and grounds to the pcm are good. Its best to backprobe while its plugged in and loaded. You should also next disconnect all 3 wire sensors to see if your 8v line comes back. The cam position sensor is also 8v feed.

It might be beneficial to get a single vehicle subscription to alldata.com. There you can access all the repair info you need for a full year. You can get all the detailed wiring diagrams, repair data and service bulletin info. It has been info second to only factory info in my experience. I think my Ranger access ran about $25.00 or so.

Thanks for that web-site. That was the best $25 I ever spent.

Well boy's I finally fixed the Jeep. What I found while I was tracing all PCM wires was that
the fool that installed the after market cell phone decided to spice the first hot wire that
he could find under the hood. The wire that was chooses was the main power to the PCM. A 10 amp
fuse was installed and the phone and the computer were wired together after this 10 amp fuse.
The new fuse and wiring was nicely tucked back into the wiring harness and could not be seen.
Funny thing, everything that I read says that I need to have the new PCM programmed. It runs
just fine without it. Thanks for all the help and suggestions.