Fan sometimes don't work

May be the AC fan, does it change when you speed up the fan or stop when you shut the fan off ? If so, the bearing in the fan motor is going dry.

without actually hearing the noise , there's no telling what it could be. a few things come to mind .a relay or signal flasher , a piece of trash in the blower fan blades , or an actuator for the vent doors trying to reset itself. a good scanner can tell you what you want to know , except for trash in the blower fan.i use a snap-on soulis pro. usually you plug in under the steering wheel to a 6 pin blue conn. for the GEM module. it tells you all about the things that are going on in the interior of the vehicle. with a good scanner you can actuate things to see them work.fun to watch too .

You need to pull the blower motor (under dash on pass side) and vac out the debris that is in the ducts. If the fan is turning, you may have had a mouse take up residence in the heater, and there is stuff hitting the blower as it turns. Hope this helps.

no you don`t need to disconnect the battery to work on the blower motor.just remove the motor and check the condition of the squirrel cage(not damaged) and check inside the air box for debris and clean out.make sure the noise is not the blower motor itself.

the blower motor is under panel near glove box. remove connector then the 3 mounting screws that hold it in. if changing the motor, use old fan cage from blower to new one, remove retainer clip to take off of motor shaft. CARL,

It is NOT the motor itself in this case, it is the blower motor's resistor pack, which was and seems still is a common problem with the grand cherokees. It is usually located under or behind the glove box right on the firewall, and some rarer cases under the hood, also on the firewall but on the hood side and not the inside of the vehicule, next to the blower motor assembly. In your case it should be located inside the vehicule and requires removal of the glove box according to a few tech experts on the web. Here is the section of tech info i have found which i think will be the most useful for you:

"Get to the blower motor in a Grand Cherokee by first disabling the airbags. Unscrew the glove box and remove it. Unscrew and remove the blower motor wire harness found directly behind the blower motor. Unscrew three screws holding the blower motor into place and then remove the motor."

So I hope this helps you out.

the blower is under dash buy glove box. remove electrcal connector, then remove the screws that hold it in, then pull it out. you can buy a replcement blower at any auto parts store. use old fan cage to put on new motor shaft.

You have to take the glove box off and it is right behind it, need a #20 Torx to take it replace it. The glove box is the hardest part of the job, I just replaced mine on an 05 Grand Cherokee but it didn't fix it for me, was well worth the $8.60 to try though.

my jeeps wiring harness behind the glove-box only needed adjusted do to rubbing of the rear of the  glove-box

If it is the radiator fan check the relay connected to the thermostat. If it is the dash fan check the relay system under the hood, and possibly behind the glove box for a blower relay.