interesting heater issue 99XJ

well Picked up Ryans old jeep, heater worked on the ride home, few days later it did not. after messing with the wires my brother burned himself and we soon realized the wires to the blower motor were bad. there was a short somewhere and it had melted the rubber plug causing them to not contact the terminals so the motor would not spin. i added some wire, cleaned it up and then put blade connecters on the end which i attached to the motor.... it works!!

week later it stopped so i wiggled the wires and it worked again...
now, if the jeep is cold and i start it blower works in a 4 settings and very strong on 4. once it warms up it starts slowing down and eventually stops working altogether. i go under the hood and move the wires around it will work again but, once it does for a while it stops.

i'm guessing it's time for a new motor right? i have a new one in the jeep now i just need to put in once i get the correct wiring connecter.

what could be causing this?

Corrosion or bad contact at the spade connectors? Possibly a bad motor ground.
Try using a little dielectric grease on the connectors after cleaning them.
Try running the motor until it stops running and see if the motor case is excessively hot. It could be a bad bearing that will work when cold, but locks up when it gets hot. (I'd bet on an electical though)

i bought a new blower motor today, i'll pull this one out and see if i can mess with it. if not i'll just redo the connectors and then put the new one in.

Any updates on this problem. I am having the exact issue. Thanks

Old thread but what did you do to correct this issue? I'm going throught this right now.....

Are you sure it's the same exact problem?

Most heater blower symptoms are only high speed operation caused by a bad resistor in the heater duct.

~Ron

Yes, same problem. I have all blower speeds. The blower will run most of the time on start up and when it doesn't I can wiggle the wires at the blower motor and it will run. The blower motor will begin to loose it intensity over a shirt period of time and all speeds are cut down when it begins to fade. If it fads out and stops I can pull over, wiggle the wires and we're off again. I've pulled the plug checked the wires and nothing looks burnt or discolored. I cleaned both the plug and blower motor with elect. cleaner, no improvements after that.