Hi Jeep friends, I have a 1993 Cherokee Country from Colorado, just got it. Everything works pretty good. The blower motor only works on high, no big deal, but after a big bump or a little while running it makes a loud humming buzzing sound, it's still running fine. I can turn it down and back on high and it's fine but will happen again sometimes for no reason.
it's not the relay that chatters, it's a loud humm buzz. Could it be the resistor or is it probably the blower motor or bearing going out to the fan?
Any info for an older cherokee would be appreciated, I'm going to do everything I can to keep her tight since she's very solid for the year. Best I've ever seen in Michigan. I plan to get everything cleaned and under coated. Any info to help preserve her would be appreciated also. Thanks everyone.

 

Right there with ya on getting as much info as possible lol I myself have a 93 Laredo with some blower issues... Good luck!

 

This is most likely not your problem but going to throw it out there.
In my '00 XJ the blower motor started making weird noises. Thought to myself great. I get to replace one.
Not the hardest thing on an '00 but not the easiest either.
So I blew out the motor from the engine bay side, no joy, and then removed this cover under the dash to see what I could see.
So there is the plastic grate and behind it I saw what looked like a piece of paper. So I gently pulled it through the plastic grate with some needle nose pliers.

Sometime earlier I had my body guy deal with some rust issues on the hood and roof. He being proactive told me he did the cowl too because if he did not it would have looked like crap.
Well the only thing I can think of is that disc fell down in there and worked its way in the blower motor area so the hamster wheel could hit it.
Unsure how long after but it was awhile after the work was done.
My point is yours could just be built gunk and stuff kinda doing the same thing.

 

Good chance some rodents packed the "squirrel cage" of the blower motor with crap.

You can see up in there with the heater controls in the correct position, up under the passenger dash.