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key off draw, odd whining noise, dome lights dimly lit

87manche

NAXJA Forum User
Location
Ohio
well, this 97 here is in deed cursed.

Key off draw is randomly 4.5A, sometimes less, still always well above the 50 ma level.

Weird things

HVAC blower occasionally doesn't shut off with the key. Pulling the IOD or Blower fuse will turn it off.
Pulling the IOD fuse kills the current draw (and the dimly lit dome lights)
Sometimes there's a high pitched whine from the engine compartment, corresponds with key off draw. Pulling fuses kills whine.
Turning on the dome lights will kill the excessive draw and show 800ma, in line with two light bulbs.
Before I pulled the rear defrost relay the indicator light would glow with the dome lights. Pulling the rear defrost fuse in the PDC killed the current draw. (for a day)
Sometimes the gauge cluster works with no IOD fuse, sometimes not. Always with. When the cluster works and no IOD fuse it appears that the alternator isn't charging battery.
radio wiring was a mess, but I fixed it.
washer bottle was missing and wiring hanging, it's been taped up, no change. Sometimes the low washer light comes on even though it's not hooked up to anything.
Grounds on the side and back of the engine have been cleaned and checked. I have not gotten to the one in the rear by the hatch yet.

I can't find any single point where these circuits all interact or are connected.
starting to suspect the ignition switch having some sort of short, but how does that ground through the dome lamps?

looking for ideas.

97 4.0 ax-15 231
 
Inspected/tested the commonly faulty drivers door and the tail gate wire harnesses for damage and short circuits ? I would also inspect the relay, relay socket, and wire harness for the blower motor. They can overheat and melt.
 
OMG, what a mess you've got on your hands. Sounds like you've got a few things going on.

First, Tim is right on target on the blower motor. High amp draw from a worn out blower motor can cause the electrical harness to melt at the switch...certainly worth a check.

With regard to the IOD circuits, there is a lot of stuff going on there. Common components you mentioned in your post are the radio circuit and the instrument cluster circuit and dome lights.

According to the 97 FSM, the IOD powers the glove box lamp, left courtesy lamp, right courtesy lamp, dome lamp, cargo lamp, visors lamp and also feeds power to the instrument cluster microprocessor, the transmission TCM and power to the radio to keep the presets in memory. There is a whole section in the FSM on troubleshooting excessive current drain related to the IOD circuit, and a search of the wiring diagram shows at least 7 drawings of circuits and components that are powered from that one IOD fuse.

7 wiring diagrams related to the IOD are probably a bit much for posting here, but I am happy to put them in an online dropbox for you to download if you think it will help.
 
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would be nice. I've only got a 99 FSM and they are different apparently.

blower motor wiring is fine. I had a look at all of it when I fixed the radio.
I haven't inspected door harnesses.
I suppose I'll do that this afternoon.
 
Check your regular mail. Give it a bit of time for all of the files to upload. There should be 9 files there when its done. It should help out a bit.
 
it's still completely random.

I have disconnected all the hatch wiring.
inspected all the door wiring and pulled every dome lamp switch.

sometimes I meter it and it's 200ma, sometimes it's 4+A.
no rhyme or reason. Sometimes the blower motor doesn't shut off with the key, other times it does.
Sometimes if I put the rear defrost relay in it draws current, sometimes not.
and a new wrinkle, I shut the drivers door and the aux cooling fan kicked on. It's only done that once.

figure that one out.

What I don't understand is that this thing sat in my driveway for 2 months and didn't kill the battery.
 
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that's what I got after I put all the switches and fuses back in. Nothing that I did should have fixed the problem.

I put the rear defrost relay back in and that will instantly jump to 3.5A.

remove it and it dropped back to 30 mA.

I can't imagine that it's a short back to the hatch, because nothing energizes that until the relay kicks over, so whatever it is is before the relay, and on the circuit that powers it or the coil. Super odd.

yes, I swapped relays to rule out a bad one.
 
Have a read of page 8N-2. It describes the rear defrost circuit in detail as well as diagnostics. In the description, it says that the instrument cluster is responsible for timing of the activation of the defrost relay. There is a 10 minute time out timer involved and certain defrost switch activations will change the time the relay is actively sending power to the heater grid. It could be that what you are seeing is normal amp draw for the rear defroster if you are not factoring in the time the cluster is controlling the relay.

As a suggestion, you might want to go back and reread the section on the testing of the IOD circuit. The manual has you do a very specific procedure to determine the actual IOD. If you read the IOD at the wrong time, you will see erroneous IOD readings. This could explain why you are getting different readings at different times and nothing seems to make sense.
 
The defrost circuit is on page 8W-48-2. It shows the ground path for the relay going from pin 85 on the relay to the instrument cluster to the defrost switch to ground when the switch is activated. Maybe it worthwhile to check the defrost switch and see if its shorted to ground. If this circuit turns out to be the main culprit of the IOD you are seeing, you COULD bypass the wire going to the instrument cluster for testing purposes and run it directly to the defrost switch. 8W-48-2 shows you exactly which wire to clip and how to reroute around the cluster. If this fixes the problem, it is suggesting the cluster timing circuits are the original problem.
 
One thing you can try is remove the cluster and re-test......Maybe it's got an internal fault causing all your goofy symptoms.....related to current draw that is.
 
cluster timing.

it's a cluster alright.

I know AMC couldn't wire a vehicle, but at least fixing their disaster is straightforward.

I really hate all this everything controls everything else nonsense.
Big fan of a switch that controls a relay directly.
 
mystery solved.

interior fuse block nearly caught fire last night.
PO had replaced antenna wire and left the grommet out, so saltwater has been running down the wire and all over the fuseblock.
It's in bad shape. Fun times it will be to repair.

Explains why it was completely random and involved multiple circuits, because every connector I pulled last night is green and nasty.
 
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if you own a late model XJ, I highly suggest you take the hour and inspect your junction block.

this was a PITA to bodge together a solution for a DD.
IMG_20150213_221649_079_zps4fq1bh4s.jpg

IMG_20150214_001431_822_zpslasgbpbh.jpg
 
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