nwguy

OK here is the deal. A 2000 4dr XJ about 160,000. Leads a pretty easy life even in the winters here. Gets driven about 150 miles a month right now. Heater started making a light clicking noise like something was hitting the impeller blade. (acorn bits, oak seeds, small twig pieces falling from trees it all gets into things around here.)This started about a month ago but other than a little noisy everything worked fine. Then 2 days ago drove it about 50 miles, parked and it was running all was fine then all of a sudden there was this heavy black smoke pouring out of the vents and from under the dash and I literally thought the car was going up in flames. I shut it down and got away from it... waiting for the flames which never came. I got a ride and didn't get back to it until today, 2 days later.

I got back to it, figuring it was the heater fan that was the problem. I pulled the fuse and started the Xj and it ran fine as usual. The smell of the smoke still hung inside the car. It is 0 degrees out and the car is frosted like a cake. I need to get the fan moving if I have a prayer of getting it home.
Get the engine nice and warm, plug the fuse in and stand by with the extinguisher. The fan is quieter but still a little clicky. It runs up and down through all the speeds. Switch the system to defrost and everything works and it thaws the windshield. I drive it back home after it thaws and it works perfectly, no smoke just the residual smell.

the smoke when it came was a heavy dark almost black that smelled electric and oil at the same time. It filled the car and at the peak you could barely make out the other door it was so thick. NOW, no smoke of any kind. All fluid levels are right, so no accounting for oil or whatever. No visible leaks anywhere. Other than the residual smell there is nothing to indicate anything happened.

I live in northern Mich in what many call the middle of nowhere. Chipmunks and mice are always invading a vehicle that sits too long to make nests. But the XJ gets used enough to not be a problem. BUT it is also winter here and now it sorta concerns me about being in the middle of nowhere in sub-zero temps and have my car go up in flames.. or smoke me out again.

Anyone got ANY idea where to look to not have that happen again?

thanks

foreveryoung001

Hey, you're up in my neck of the woods. Wouldn't be surprised if you did have a critter in there. My XJ is my DD and I still have something bunking in there. Don't know if it lives in there or just comes in at night for the warm engine, but its gotten inside my Jeep and eaten snacks and things I take to work and keep in my glove box and center console.

I don't know how a critter would cause what you described though.... My first thought is some type of rubber seal or o-ring on the fan must have over heated and burned off, but I don't even know if that would be a possibility.

Curious to see what you find out. I'll be watching this thread to see if you find a cause and/or solution.

ehall

There's no cabin filter on these things, so anything that can get in the cowl has the potential to get sucked into the blower and heater core. Could also have been any of the electronics, including the blower motor itself. I would pull the blower out and take a look, pull the resistor pack and smell it, pull the blend door and look around, etc

Larry's XJ

In addition to above, check ALL fuzes, under dash, behind kick panels for burn.

nwguy

WELL, I have done everything but tear the dashboard apart. All fuses in every location were fine and not popped, burned, broken, open, whatever.

I finally in exasperation took it to a far place in the yard, turned the heat on high and started it up and just walked away. Half hour of idle time later and the fan is still making noise, the smell still lingers and nothing else. No smoke, no smell of burning wires or anything else.

Have driven it a couple of times lately and nothing but a noisy fan.... and the lingering smell that every now and then gets stronger then goes away.

Short of disassembling the dash or puling the fan(it has air) do not have a clue.


Suggestions?

extrashaky

I have never pulled the dash on one of these, so I don't know the answer to this: Is it possible to run an inspection camera up in there to potentially see what's going on? I have a Harbor Freight inspection camera on the end of a three foot flex cable. I'm thinking maybe run it down through the vents or up under the dash somehow to get a look where the sun normally doesn't shine?

Larry's XJ

Seems i've seen mention of wires/connectors related to fan melting. Might pay to look closely in that area. Weird that you had what sounds like an elec fire/problem, yet no blown fuses.
Just may have to pull dash and or blower to look.
Was just as cold in Lapeer as it was in Mio this morn, so maybe it will warm up a bit soon, unless you have a garage to work in.

foreveryoung001

All of your symptoms point me towards a bad fan... EXCEPT that part where it sounded like you were on fire... I could see a slight burning smell if something was wedged up in there, heating up the plastic fan blade or something.... but smoke.... to the extent that you had it... I'm stumped too. Still watching to see if you ever figure out what is going on with it.

foreveryoung001

Just a thought... are you the original owner? The PO of my XJ did some things that I will always question. One of them was running some kind of wiring, I'm guessing they were some kind of light that he removed before he sold it to me, but the wiring was still there, and when I realized it wasn't hooked up to anything and pulled it out, it had bypassed the fuse panel. He had it hard wired to the battery, with just a simple on/off switch controlling it.

Perhaps the PO of your Jeep rewired the fan and bypassed the fuse panel? Just a thought, but might explain why you aren't getting any blown fuses.

ShowMe Cherokee

Check the blower motor resistor. In my truck I have had critters drop foam insulation and other junk down on the resistor, which heats up and then fails. I've never had smoke, but the resistor looks burnt when I've replaced it (twice now, stupid mice).

If you can get all 4 fan speeds then the resistor is still functioning, but that may be the source of the smoke.

Bobolink

I second the nomination of the resistor pack. Those suckers are really hot, and are hottest on the lowest speed (because all resistors are in play to run the motor at the lowest speed) and if the air that normally flows over them gets blocked by any kind of debris, such debris won't sit there for long before igniting. On the highest blower speed, there is no current through the resistor pack, since in that configuration, all power goes to the fan motor.

nwguy

I personally knew the first owner and bought it direct from her. All she ever did was plug a CB into the dash with a cigarette lighter adapter.

the only thing I ever did was put a couple of Daylighters on it before my kid took it away to college up to Houghton in the U.P. Lotsa miles of rural roads so he needed all the light he could get in front.

Then when he graduated it went to the other kid for a college ride. almost 9 years later I got it back with 150,000 on it. Never had any issues of any kind.

Then about 10,000 miles later I had the incident I described above.

As for fan speeds, have them all. All switches work, all ducting works, everything is just as it was before I got smoked out of it. I kid you not, I could barely see the passenger door from the drivers seat. I really was looking for flames to appear.

At this stage I have talked to one of the local Jeep dealer mechanics and he just scratches his head because as I said, everything works and no fuse problems of any kind. He said the only way would be to remove the dash and look around.

Bobolink

What I was getting at with the resistor pack is just to have a look at that before you go to all the trouble of tearing into the dash for no reason. The resistor pack is easy to remove, and reinstall. On something like this that's only happened once, and has not occurred since, I'm suggesting that the resistor pack burned something that got hung on it, and now that that something is burned up, you won't see the problem again. You might be able to see that something got cooked by the resistor pack, then you won't have to worry about it anymore.


I also pointed out that on high fan speed, the resistor pack is completely bypassed, so you would never have it occur in that configuration, no matter how long you ran the fan.

nwguy

AND FINALLY
got around to figuring out how to pull resistor from the Cherokee.

It was burned and had bits of paper towel unburned still inside the cage. It also had bits of charred paper.
It worked but the smell came and went.

ANYWAY

Got the resistor changed and it definitely was the cause of the smoke because there was fire, just lucky it didn't go anywhere.

The fan is still making a lot of noise like something is in there rubbing against the cage so I am going to have to pull it. The Jeep has air conditioning so it has to be through the front and that looks like fun.
BUT

that is for another day.


THANKS to all who offered assistance.

Great site to belong to.