Blower Fan slowing down randomly on A/C

EDIT - This was supposed to be in OEM tech. Sorry!

I have searched for this issue, but have come up with nothing that is the same as what we have.

My wifes cherokee, Bone stock 96 sport, 4.0l 4wd, aw4, 195,000mi etc etc. I also have the same year and model jeep, but with fewer miles. Both of our jeeps only have the 'high' setting on the blower motor, I know how to fix that, but just havent gotten around to it yet. Thats not a problem, but MAY be contributing to this new problem?.

Her problem is this. When you are driving with the A/C on, the blower fan will randomly slow way down for no reason at all. It does not stop completely, but almost. This is NOT the similar deal where there is a vacuum leak and it starts blowing out of the defrost vents under acceleration. I have that issue on my Jeep, wich I am tracking down.

Her problem will surface at any random time, while accelerating, maintaining speed, decelerating, or even just idling. It acts as though the voltage to the blower motor is sagging. I replaced the alternator about 10,000 miles ago, but I dont think that is the culprit. I have watched the volt gauge while its doing it, and it doesnt sag or move. Nothing else happens to the jeep while this is happening, no dimming lights, no running issues etc. It only lasts for a few seconds, and then it goes back to normal.

Anyone else have an issue like this one? Its not the end of the world, but its annoying. I her told we may have to just wait until it breaks completely to figure out whats going on with it...

Thanks in advance...

~ Stump

could be grime on the contacts

it might also be the circulation door is flopping around--that will sound like the blower speed is changing but it will just be change in volume not air velocity (put hand in front of vent to check this)

ehall said:

could be grime on the contacts

it might also be the circulation door is flopping around--that will sound like the blower speed is changing but it will just be change in volume not air velocity (put hand in front of vent to check this)

Click to expand...

Agree, could be in the HVAC head unit, the motor, a ground issue, any number of things.

As you have two identical year XJs, you could swap one thing at a time until the problem is found.

And yes, replace the resistor pack. In fact, until that is fixed on both vehicles I wouldn't try and fix anything else. Fix the known problem, then go to the next, and so on, especially when they are in the same circuit.