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Jeep grand cherokee 1998 interior lights stay on

8K views 13 replies 6 participants last post by  petermen1478 
#1 ·
Hello all,

I have a jeep grand cherokee 1998 and I am having trouble with my interior (dome, courtesy? not sure the proper term) lights staying on when the car is not running. If I start the engine or if I put the ignition in ACC the lights turn off an act normally (I can turn them on or off by pressing on them). I am an extreme nooby but I would really like to fix this problem myself.

I checked 5 times that I did not move the light switch on the dash all the way up.

The 10 red fuse seems to be working fine, I took it out and looked it over and it is not blown. I tried replacing the courtesy lamp relay with another relay (parking light relay) and the problem persisted.

Removing the courtesy lamp relay turns the lights off (however I can still turn them on and off manually after that), removing the 10 red fuse turns the lights off and I can't turn them on or off.

I was hoping removing the fuse or relay would at least stop the battery drain on the car but the battery is still dying even without the fuse or relay (which is frustrating because I wouldn't mind not having lights while I fix the issue but now I cant drive the car). Should I try removing both at the same time?

I removed the interior trim from the rear hatch and tried to disconnecting the two wires that fed into the glass switch and it didn't seem to fix the problem. I tried to disconnect the wire that went to the hatch switch it didn't seem to work but I am not sure I disconnected the right one as I couldn't find any wiring diagrams for the back hatch. I am disappointed this didn't work as it seemed to be the main culprit for everyone but I probably did not disconnect the right things.

I check the door switches and tried pressing each one manually with the door open to see if one of them was faulty but that didn't do the trick (however if it was the door switch i think the lights would stay on when the engine is on?)

I had just gotten the AC serviced before this started to happen (they vacuumed the system out and filled the freon, no obvious leaks detected). I also noticed at the same time that the break lights sometimes seem to stay on after I turn off the car but this could be an unrelated issue as I remember this happening before too (I just fiddle with the break pedal until they turn off)

My next step is to try and unhook the light switch on the dash to see if its sending a wrong signal.

Any guidance would be appreciated.

Cheers,
 
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#2 ·
The brake light staying on, and it being remedied by messing with the pedal, would seem to indicate a bad, or mis-adjusted, brake-light switch. That's a common failure item, and is only $15 or so to replace.

The interior lights are "told" to stay on for a minute or so after shut-down by the computer (BCM?), so that would be normal. You probably know that already, right?


There have been posts about guys having a pinched wire above the overhead console that can cause your type of issue. It's a minor hassle to remove, and it's difficult to do without messing up the headliner material on the sides, so you might want to try other things first.
 
#3 ·
The brake light staying on, and it being remedied by messing with the pedal, would seem to indicate a bad, or mis-adjusted, brake-light switch. That's a common failure item, and is only $15 or so to replace.

The interior lights are "told" to stay on for a minute or so after shut-down by the computer (BCM?), so that would be normal. You probably know that already, right?

There have been posts about guys having a pinched wire above the overhead console that can cause your type of issue. It's a minor hassle to remove, and it's difficult to do without messing up the headliner material on the sides, so you might want to try other things first.
I will check the switch for the brake-light, any idea where located? Or where I can find the information myself?

Yes the lights used to stay on for a short while and turn off, now they just stay on no matter how long I wait.
 
#4 ·
It is part of the pedal assembly IIRC.

The best reference for the ZJ is the factory service manual. You can get electronic copies online for a reasonable price or find a hardcopy on ebay.
 
#6 ·
Ok here is a small update, I found the wiring diagrams using the FSM and was able to identify the correct liftgate ajar switch which is really inside the latch housing for the lift gate. I have disconnected but the problem persists.

Meanwhile the batter had died in the car and the CAA battery technician mentioned that with everything off something is still pulling 0.4 to 0.8 A on the battery (the courtesy light fuse was taken out during this period).

Another thing I noticed was that when I arm the car alarm the horn doesn't honk anymore. The doors all lock and the little red light starts to flash but no honk of the horn. Someone in another thread mentioned that the lock cylinders can send a signal to the BCM to turn on the lights if the wires are grounded (yellow and violet wire). I dont have any tools to check if they are grounded, is there anything I can do to test this theory by unplugging something?
 
#7 ·
To find your battery drain you can test across the fuses with a meter set on millivolts DC. With the key off for about 10-15 minutes to let the PCM & BCM go to sleep, check for voltage across the test contacts on the back side of the fuses. If there is current running through the fuse there is enough resistance in the fuse to show a few millivolts difference between the two contacts. Take notes on which fuses show the voltage, there may be several but it will point you in the right direction.

GW
 
#8 ·
If you pull off the door panel you can reach up and feel the wire attached to the lock cylinder and follow it. If I recall correctly I think it goes down to the outer corner of the door and is attached with a clip where you can unplug it.

I spent some time trying to track down the cause of the same problem when they miraculously started working again. It worked great for about a month. Right now I have things disconnected so it doesn't kill my battery.

Good luck with it.
 
#9 ·
If the red light is blinking then the cylinder switches aren't grounded, the jeep knows it's locked.

But you can confirm that by leaving a window open, arming the alarm, and then unlocking from the inside and opening the door. If the alarm goes off then the alarm is working and the cylinder sensors ain't it.
 
#10 ·
Ok so I opened the driver door panel and unclipped the yellow/violet wire and the interior lights still did not go off (kachink you were right, outter botom corner)

So i then performed your test, where i locked the car with the windows down and open a door handle and nothing happened.

I also checked all the fuses in the box near the battery and they all seemed fine, except now the horn makes a sound when i lock the car with fob which it wasnt doing earlier today so I guess thats one problem that solved itself?

So now I dont know what to think, unless its the passenger side lock cylinder thats malfunctionning?
 
#11 ·
Major Update: Its fixed!!!

It was the passenger side lock cylinder anti theft switch (yellow/violet color) once i unhooked it it worked, however the whole horn and alarm system must have had an impact because since the horn started working the interior lights would flicker once when i would lock the car instead of just staying on. So two things: whatever I did to the fuse box near battery fixed the horn, and unclipping passenger side lock cylinder anti theft switch.

Now for the second problem discovered, the drainage on the batter:

Goldwing suggested measuring the fuses, a few questions since i havent done anythng like this since physics classes:
1) is that with a voltmeter?
2) when you say back side of the fuse do you mean the two metal dots on head of the fuse? I am not sure where the test area is
3) Do i check all the fuses in the fuse box near battery and the fuses in the BCM?

Also please let me know if I am supposed to open a new thread for this stuff

Thanks
 
#13 ·
1)Yes it is with a voltmeter (multi-meter)

2)Yes the two metal dots on the back of the fuse let you test in place.

3)Check the fuse box by the battery and the one behind the passenger kick panel. I am not familiar with fuses in the BCM.

GW
 
#12 ·
If the system is working then your BCM should now go to sleep properly and you shouldn't have any parasitic draw. The BCM was staying awake while the lights were on and causing significant current draw even with the fuse for the lights themselves removed.
 
#14 ·
I had this Problem with my 98 Jeep Grand Cherokee Laredo and tried troubleshooting it for days and almost gave up.

I encountered this problem after changing out my drivers door electronic lock. 4/18/2020

Somehow I broke the ARM / DISARM switch that attaches or snaps onto the Door key lock cylinder
inside the door.

This is the switch that arms and disarms the Anti-Theft alarm when unlocking/locking the vehicle with the key specifically.

I found the purple/yellow wire (for the Switch) going thru the (rubber boot) door harness between the drivers door
hinge side and the underdash. I pushed back the rubber boot and cut the wire dead center and with my OHM meter,
I read a short to ground from the switch.

After cutting the wire to the switch I discovered everything was now working properly with
the exception of being able to Arm or Disarm the Anti-Theft alarm from that drivers door
because I eliminated that switch by cutting it's wire.

My Dome lights went off finally (30secs.) and now work properly.
My alarm works as well and the Dash alarm LED is blinking Red again when armed.

All that is left to do now is to purchase one of these switches somewhere and I'll have finished the job!!!

I hope this solves your problem as well...

Note: it could be the problem is one of the other Arm/Disarm keylock switches besides the driver side.
There is 1 located in the back hatch Keylock cylinder and another switch on the Passengers side key lock..
 
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