Unknown XJ

Afternoon folks, it's been a while since I last been on here,let alone contributed anything.....

My family and I took our XJ out for a ride today that was pretty uneventful to say the least. The heater worked great and in fact, I was getting quite hot. (Rode about 30 miles on the interstate at 70+ MPH)
When we were done with our visit with the in laws, I jumped in the Heep and started her up and then turned the heater on....and nothing happened. I checked the fuses and they checked out fine....popped the hood checked the junction box in there and they checked out. We decided to press on and hurry up and get home (our boys (9,6 y.o,&3 months)were getting anxious to get home to see if Santa brought anything new lol)

When we was going down the road my wife and myself noticed that there was some heat coming out of the vent,but it was weak at best. Moving the settings around and I heard the blend door moving....it just wasn't blowing hard.

Could the blower crap out without warning? Could it be the switch perhaps? Has any of this ever happened to you folks? I told my wife that she was messing with us cause My father in law and myself was talking about how to flush his heatercore on his 2000 Dakota.... Any ideas folks?

Thank you for your time.

Unknown XJ

Forgot vital info for my XJ:
1998
4.0I6
AW4 tranny
NP231 TC
D30 HP front
C8.25 rear
191,000 miles
The last five probably doesn't matter anyways.....

Unknown XJ

So, through extensive Googling and running of tests,everything pointed to the blower motor resistor.....I pulled it out and it was crusty as hell....I swapped it out, and no dice.....any suggestions folks?

Unknown XJ

I can also hear the relay behind the glove box click when I turn the key....I'd imagine that if it was out it wouldn't do anything.....

Turbo X_J

Dash switch or melted connector, what kind of voltage are you seeing at the motor?

Unknown XJ

Nothing is melted or has a burning smell....I'll have to check the volts and report back.....

Unknown XJ

There's power going through the harness to the motor....
My buddy held the probes while I switched the speeds in the cab....
How would I go about testing the motor or the switches?

betsi1121

I had insulation wrap around my blower motor. It was super easy to get to and replace. I pulled the windshield washer reservoir and 3 bolts later it was out. Might be a time-saver to pull it out and make sure it isn't something obvious.

Jimbo Slice

^^^ This.

Had the same thing happen on my '89. No burning smell or anything. Pulled the switch out and found the stock wire harness was melted.

Simple fix was to crimp on new terminals to the wires and reconnect.

Blows like a high class ho now.

Unknown XJ

Well, when we pulled the harness off the blower motor and put the probes on the pins, I started at speed one and moved slowly to four. My buddy said that on his meter, the current would step up with each higher speed. And as far as the other switch goes, I reason its good too cause I can hear the AC clutch cycling on and off like it normally would....
One thing that we weren't sure of is the fact that we pulled the relay behind the glove box and put the probes from terminal to terminal and only on one of them there wasn't any current going from it.....but you could hear the relay clicking though when you hit the key.....the mystery deepens for sure..... please,by all means, keep the suggestions coming folks....I'll pull the motor and look into it before I write it off....

It just seems weird to me because 1: the motor made no weird sound before this happened (let alone ever) seems like it would get weak, squeal, or something.... it was the same as its always been since we got her in March 2011. And finally 2: When I would turn it on I usually turn it all the way up...but if you step it down to three, there was a dramatic difference between three and four....in fact, one,two,and three were the same......just honestly didn't think much of it ; just wrote it off as a quirk of Jeeps. :-)
Thank you folks

goatherder

I just went thru this - its a pain in the a$$.

Check this thread for some valuable info:

https://www.cherokeeforum.com/f2/199...n-help-123605/

'90Cherokee

The motor can die without warning depending on it's fault. Sometimes giving it a smack while it's powered will make it run again and it'll continue to work till it stops on the dead spot of the commutator. Had this with fuel pumps, fans, blowers, water pumps on boats, any motor with brushes. The noisy motors are because of failing bearings which my XJ started doing yesterday so I need to lube it before I loose it. I rather fix than replace when possible.

'90Cherokee

BTW, you had a little bit of heat while driving because the outside air is being pushed through the system. If you were to crack a front window (wing window on early models) it'll create a vacuum in the cab helping pull air through the system. Rear windows will tend to blow in so it has to be a front. If it's not shytti cold outside it'll heat better than staying closed up.

Unknown XJ

Awesome.....Thank you very much.....Almost sounds like the drama I'm going through....I'm going to look into the check vacuum lines.....but my blend door works as it should though but onbthe other hand, I've never had cruise control since I've had her....just never looked into it either lol.

Unknown XJ

It's funny cause I kept my window cracked to keep the windshield from fogging up so bad and it has been cold here these past few day... I'm having freezing rain here ATM....


I'll report back my findings when the sun comes up...gotta start getting the boys up and off to school.....hopefully this will be the last cold ride in my Heep....

I knew I would find some info that was evading me here...I love this forum. ;-) If everything goes according to plan (te he plan) I should have awesome heat after this is resolved. I flush my core, block,and radiator and refill with fresh coolant every spring and I've gotten pretty decent heat because of it.

I suppose my Heep wanted some Christmas presents that I wasn't prepared to buy lol. Merry Christmas everyone!