Jeep Electrical Issue - 2003-04 Mach 1 Registry Owners Club

iudelt89 · 07-19-2013, 11:05 AM

Hey guys, already posted about this over on the Jeep forum, but figured it couldn't hurt to see if anyone on here had any ideas about this. I've had batteries die in my cars before, but have never had any electrical symptoms like this. I'm still thinking it is battery related, but the symptoms are very strange. I apologize in advance for the long post, but any insight would be appreciated

So my Grand Cherokee has been doing some strange things recently, and finally will not start without a jump. A few weeks back I turned on the ignition and the guages started jumping around all over the place and it wouldn't start. No clicking, literally nothing. I turned the key to accessories on and off a few times, let it sit for a minute or two while the guages continued bounce all over the place, then it reset itself and started. Everything worked, all power options, radio, guages, etc.

After that point however, the trip meter, avg mpg, and pretty much everything in the overhead computer kept resetting randomly when I would turn the car off then on again. Once it was running though, everything was fine and worked normally.

So fast forward to this morning. The car won't turn over at all, and the guages are bouncing all over the place even when the key is not in the ignition. The interior lights came on, but are extremely dim. There is a clicking sound coming from one of the relays behind the fuse box in the driver's side footwell. I tried disconnecting the battery for a while, no dice. I was able to jump it, and once started, everything worked fine again. As soon as I turned the car off again, the guages started boucing all over the place even with the key out, and once again it will not turn over at all.

I had the alternator and battery tested a couple weeks ago after the first incident, and everything was fine. They recommended I replace the PCI bus and guage cluster due to what I was describing. I was thinking this might be a PCI bus issue, but the symptoms don't match what I've read about it and its not exactly a cheap part. I don't want to replace the guage cluster, because it works perfectly when the car is running. The last thing I want to do is just start replacing random parts. I'm thinking it could be a bad relay because of the clicking sound, but then why would jumping it work? I am completely at a loss here and I can't seem to find anything about this happening on the Jeep forum. Anyone have any ideas as to what this could be? I'm thinking maybe a bad ground somewhere?

bris09 · 07-19-2013, 04:48 PM

Sounds like a low voltage issue. Check the cables for corrosion. Check to make sure there isn't a loose connection on one of the wires coming off of the battery.

shadowmaker · 07-19-2013, 06:38 PM

What yr? 95-98 by chance? Do you have the alarm? If so, check the plug that says the rear hatch is open. The rear hatch switch is a known problem. Caused me 6-9 months worth of hell and 2 batteries.

If you want to test it without costing any money, unplug it. Let me know and I ll see if I still have the pics if you need them.

FL Mach 1 · 07-20-2013, 01:09 AM

Kind of along the lines of what bris mentioned with corrosion. I have had to replace battery cables on a few foxbodies that exhibited similar issues. The cables looked good visually but they must have corroded under the insulation. May be something else to check.

iudelt89 · 07-22-2013, 10:10 AM

Its a 2000 WJ. Ended up cleaning some corrosion off the cables, cleaned the grounds, replaced the battery and all is well. I've never seen a car act like that because of a low battery. Really strange, but I'm relieved it wasn't anything serious.

What really threw me was I had the battery and alternator tested 2 weeks ago and was told everything read normal.

devous1 · 07-22-2013, 11:11 AM

Bad grounds do all types of **** to your electrical system. I was driving my Dodge 3500 one day, the radio went out on the way home. Then it started loosing power but I managed to hobble it home. When I got home I noticed dripping under the truck and the primary battery was boiling over. Which was great because I had just replaced my driveway a few weeks before that.

Checked the batteries with the truck running and they were around 19v and started to boil over again almost immediately. So I cleaned all connections and good as new.

mach18604 · 07-22-2013, 03:46 PM

I had to get rid of my 06 Grand Cherokee because it leaked water where the roof was put on.. causes lots of issues to the main harness..

good luck

07-19-2013, 11:05 AM	#1
iudelt89 United We Stang Join Date: Jun 2011 Location: Libertyvile, IL Posts: 985	Jeep Electrical Issue Hey guys, already posted about this over on the Jeep forum, but figured it couldn't hurt to see if anyone on here had any ideas about this. I've had batteries die in my cars before, but have never had any electrical symptoms like this. I'm still thinking it is battery related, but the symptoms are very strange. I apologize in advance for the long post, but any insight would be appreciated So my Grand Cherokee has been doing some strange things recently, and finally will not start without a jump. A few weeks back I turned on the ignition and the guages started jumping around all over the place and it wouldn't start. No clicking, literally nothing. I turned the key to accessories on and off a few times, let it sit for a minute or two while the guages continued bounce all over the place, then it reset itself and started. Everything worked, all power options, radio, guages, etc. After that point however, the trip meter, avg mpg, and pretty much everything in the overhead computer kept resetting randomly when I would turn the car off then on again. Once it was running though, everything was fine and worked normally. So fast forward to this morning. The car won't turn over at all, and the guages are bouncing all over the place even when the key is not in the ignition. The interior lights came on, but are extremely dim. There is a clicking sound coming from one of the relays behind the fuse box in the driver's side footwell. I tried disconnecting the battery for a while, no dice. I was able to jump it, and once started, everything worked fine again. As soon as I turned the car off again, the guages started boucing all over the place even with the key out, and once again it will not turn over at all. I had the alternator and battery tested a couple weeks ago after the first incident, and everything was fine. They recommended I replace the PCI bus and guage cluster due to what I was describing. I was thinking this might be a PCI bus issue, but the symptoms don't match what I've read about it and its not exactly a cheap part. I don't want to replace the guage cluster, because it works perfectly when the car is running. The last thing I want to do is just start replacing random parts. I'm thinking it could be a bad relay because of the clicking sound, but then why would jumping it work? I am completely at a loss here and I can't seem to find anything about this happening on the Jeep forum. Anyone have any ideas as to what this could be? I'm thinking maybe a bad ground somewhere? __________________ Black Staggered FR500's, SSS Adrenaline Cat-Back, JBA o/r h-pipe, MGW Short Throw Shifter, H&R SS Springs, Bilstein HD's, MM Bumpsteer, MM CC Plates, Kenny Brown Extreme Subframe Matrix, FRPP Alum Driveshaft, 2000 Cobra R front brake kit, MM pan hard bar, MM LCA's, K&N FIPK Intake, Bama Tune, Shaker Diverter, FRPP 3.73s, Moser 31 spline axles, FRPP diff cover, FRPP Traction-Lok diff, Kenny Brown Brake Ducts '04 Black 5-Speed Mach 1, 2000 Jeep Grand Cherokee

07-19-2013, 04:48 PM	#2
bris09 Registered User Join Date: Oct 2004 Location: Middletown, PA Posts: 3,992	Re: Jeep Electrical Issue Sounds like a low voltage issue. Check the cables for corrosion. Check to make sure there isn't a loose connection on one of the wires coming off of the battery. __________________ Brian 04 Azure Mach 1 Mods: Enough to not be the slowest, but nowhere near enough to be the fastest. 17 Fusion Sport Now faster than the Mach 96 Laser Red Cobra Vert For those days you just wanna cruise with the top down 89 Shelby CSX Still rocking the VNT and Fiberides.

07-19-2013, 06:38 PM	#3
shadowmaker Registered User Join Date: Aug 2009 Location: VA Posts: 2,136	Re: Jeep Electrical Issue What yr? 95-98 by chance? Do you have the alarm? If so, check the plug that says the rear hatch is open. The rear hatch switch is a known problem. Caused me 6-9 months worth of hell and 2 batteries. If you want to test it without costing any money, unplug it. Let me know and I ll see if I still have the pics if you need them.

07-20-2013, 01:09 AM	#4
FL Mach 1 Nitrous Lizard Join Date: Aug 2002 Location: Orlando, Fl Posts: 1,149	Re: Jeep Electrical Issue Kind of along the lines of what bris mentioned with corrosion. I have had to replace battery cables on a few foxbodies that exhibited similar issues. The cables looked good visually but they must have corroded under the insulation. May be something else to check. __________________ 1965 Mustang Convertible 200 cid 1965 Mustang Fastback 200 cid 1993 Mustang GT Convertible 2003 Azure blue Mach 1 member #13

07-22-2013, 10:10 AM	#5
iudelt89 United We Stang Join Date: Jun 2011 Location: Libertyvile, IL Posts: 985	Re: Jeep Electrical Issue Its a 2000 WJ. Ended up cleaning some corrosion off the cables, cleaned the grounds, replaced the battery and all is well. I've never seen a car act like that because of a low battery. Really strange, but I'm relieved it wasn't anything serious. What really threw me was I had the battery and alternator tested 2 weeks ago and was told everything read normal. __________________ Black Staggered FR500's, SSS Adrenaline Cat-Back, JBA o/r h-pipe, MGW Short Throw Shifter, H&R SS Springs, Bilstein HD's, MM Bumpsteer, MM CC Plates, Kenny Brown Extreme Subframe Matrix, FRPP Alum Driveshaft, 2000 Cobra R front brake kit, MM pan hard bar, MM LCA's, K&N FIPK Intake, Bama Tune, Shaker Diverter, FRPP 3.73s, Moser 31 spline axles, FRPP diff cover, FRPP Traction-Lok diff, Kenny Brown Brake Ducts '04 Black 5-Speed Mach 1, 2000 Jeep Grand Cherokee

07-22-2013, 11:11 AM	#6
devous1 Chairman of "The Bored" Join Date: Sep 2004 Location: A CORNFIELD IN OH Posts: 2,001	Re: Jeep Electrical Issue Bad grounds do all types of **** to your electrical system. I was driving my Dodge 3500 one day, the radio went out on the way home. Then it started loosing power but I managed to hobble it home. When I got home I noticed dripping under the truck and the primary battery was boiling over. Which was great because I had just replaced my driveway a few weeks before that. Checked the batteries with the truck running and they were around 19v and started to boil over again almost immediately. So I cleaned all connections and good as new. __________________ 2014 GT500 Black/Black 03 TORCH RED MACH V7 YSI and Some Other Stuff 03 DSG MACH 90 Kenny Brown Super LX 89 LX BBF as seen on Pinks 5/11-SOLD 11 F450 Lariat A Couple Tuber Buells

07-22-2013, 03:46 PM	#7
mach18604 Registered User Join Date: Nov 2005 Location: Lyndhurst, Ohio Posts: 2,287	Re: Jeep Electrical Issue I had to get rid of my 06 Grand Cherokee because it leaked water where the roof was put on.. causes lots of issues to the main harness.. good luck __________________ Collecting for an Eaton Swap down the road..

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