Ascender

Hello all.

I have a 2001 Grand Cherokee that had a leaking heater core, and so I replaced it. What a royal pain.

Now that everything is back together, the cluster acts strangely. The emergency flashers work as long as the ignition is off, otherwise the turn signal indicators are constantly illuminated dimly. there are a few idiot lights that flash in 1 second intervals, and the wipers don't work. Sometimes there is a rather loud buzzing coming from behind the cabin fuse box where the BCM is located.

The truck will start & run, but the tachometer and the rest of the gauges do not...although they do self-test at startup.

I've went through the truck, checked & rechecked the connections on the various harnesses to make sure they were seated & such...and I'm at a loss.

Beginning to wonder if the BCM decided to take a dump in the process of everything. Hard to tell, given the sheer number of connectors I had to pull to do the job.

Any help/guidance would be greatly appreciated. Thanks!
~ Asc

Noah911

I just got a new phone. It doesn't have any of my stored pictures for something I want to show you.. I am thinking it does sound like something is going on with the BCM on your Jeep too. It may not really be the BCMs fault though. It is probably something it controls wired in through it causing your issue? I had some similar type of problems in a way on my ZJ awhile back. Mine had several problems. On mine, the backlighting to some of my cluster gauges were not illuminating. My 4-wheel display in the center stopped lighting up to work too. The indicator on the dash for my left turn signal did not illuminate to blink either, but on the outside this turn signal was still working correctly and flashing how it normally should be. My interior lights would always flicker on/off on their own when driving. The drivers side window control button would control and could be used to turn my interior lights on and off too. Mine also had a parasitic drain/voltage drop in it that was draining my battery dead in only a matter of hours... There was a lot of issues.

My problem was solved though.. It was related to the floor courtesy lamps on my Jeep. I eventually found the primary fault when I backprobed the wires at the BCM connector. Doing this pointed me to the courtesy floor floor lamps as the issue which was causing all these abnormalities.

I used a paper clip, alligator multimeter clips, and two voltmeters to help me find the issue. I did several tests in various different ways to see the root problem. I kept one of the voltmeters connected to the battery. The other voltmeter was kept probed into the BCM and cluster gauges fuse spot located on the interior fuse panel.. to see what would happen when I used a jumper wire to link the BCM pins to their associated terminals on the BCM connector. When I jumpered the courtesy lamps wire together at the BCM to the BCM connector, it caused my problem to recur. It was apparent on the two meters for me to see...

It can be any of the wires there at the BCM leading to a fault somewhere to cause your problem. The rear hatch window, the lift-gate, a door switch, the glovebox courtesy lamp, the floor courtesy lamps, door locks key switch, etc...

I think if you do something along the lines of how I mentioned jumpering the wires one at a time, you may be able to possibly find your problem here at the BCM and its connector.

Or else, I think for your issues.. Maybe start by pulling off and removing each wire from off of the BCM connector one at a time. Plug the BCM connector back together to the BCM after each wire gets pulled.. to see its behavior afterwards for each wire disconnected. Hopefully, when you have the problem wire and its circuit removed it will completely go away for you when do... then you will know what the problem is that way.

Ascender

Thanks for the reply Noah. I didn't mess with it today...needed a break from it. Getting a bit long in the tooth for wrenching on these #%$% machines. LOL

I think I'll give the fusebox/BCM area/wiring a good going over in a day or 2. I wanted this truck operational for my wife's use this winter & that's looking dubious..but maybe I'll get lucky.

Heh. Got enough kids to prove that happens sometimes..

Noah911

I am not absolutely sure about the WJs and their windshield wipers? I've never had to look into it on my WJ. Although, on my ZJ the wipers get their own fuse, and it is separate from the BCM and cluster gauges fuse/circuit.

The fuse for your windshield wipers may just be blown? Is that a possibility? Maybe the windshield wipers circuit will also be another good location to investigate for the problem you are having too? If you look for the windshield wipers fuse.. maybe you find the fuse is blown? You could probe the terminals here with a voltmeter to see what this fuse circuit may be able to tell you? Look to see if there is anything else sharing this fuse with the windshield wipers, and check those places too. It might all be connected?

On my ZJ.. the rear windshield wiper blade motor, as well as the courtesy floor lamps were the two reasons I found responsible for the voltage drop/parasitic drain that was occurring on it to drain the battery (completely removing the rear wiper blade motor did not fix the other problems though). I'm not sure how much of a coincidence this is for what you've got going on with your Jeep? It could be something though...

97grand4.0

Wait, you took it in somewhere and let them replace the heater core? Take it back immediately and make them fix it.

Noah911

But, they may just go messing things up even worse on the Jeep for him? There is that to worry about..

97grand4.0

So true! That is why NOBODY works on my rig but me.