96Cherokee

Hey guys all of my heat settings work but if I hit the slightest bump my heater starts to make this really screwed up noise but then if i put it to the low setting and put it back it will run untill i hit another bump...its even starting to happen while parked...its cold winters up here in northern ontario so if you guys could give me some advice that would be awsome thanks!

JeepneyNJ

I just had this same problem about 2 weeks ago, did my research and ran some tests and finally figured out the problem. This should help...

If you put your heat on and turn the fan to 4 and it runs, but doesnt run on 1,2 or 3, then it means that your resistor is probably bad, its a quick and easy fix for about $30.

If your blower isnt running at all, it could be either your relay or your switch. The relay is an even easier fix than the resistor and only costs like $11. Not sure about the price of a switch, but you just need to tear our your switch board on your dashboard and replace it.

If it always just makes a high pitched sound, your blower motor is probably dead. A way to test it is to disconnect the harness that plugs into your resistor and connect it to a 12v battery, the green wire is + and the black is the -, if it doesnt run at all, then you know your motor is shot. (Running a 12v battery directly to your blower motor is the same as turning your fan speed on the 4th setting, but it bypasses a potentially bad switch)

all of these components are behind and under your passenger glove compartment, the relay is in plain view but to see the resistor you must take off the black panel down by where the passengers feet would be, under the glove compartment.

Hope this helps, stay warm.

If none of this works, consider this Smiley:

JeepneyNJ

Also check your grounds