Hey everytime I turn on my heat the fan makes a loud noise then stops then starts up again. How do I fix this? It only acts up when the heat is turned on.

 

That is your blower motor, the bearings are going out and it will need to be replaced ASAP as it is drawing to much power and is one of the leading causes of failed wiring in the dash which can lead to fire

 

^Yes this is very true , mine caught on fire

 

Hmm didn't know a bad blower motor was a fire risk. Guess I'll be replacing mine tomorrow.

 

Sure is if its making a awful noise then better change it . I left mine on came in the house for minute went out and smoke was rolling out from under the hood . Open hood and was flaming ,I put it out with a jug of antifreeze I had in back of her lol

 

Are you talking about the blower motor, or the extra fan mounted in front of the powersteering pump?

 

blower motor under the dash/ the electric fan is not turned on by the heater but rather by the AC

 

The blower motor in the firewall

 

It's definately my fan then. This only started happenig after I got really stuck in mud and got the tractor to pull her out so maybe I just got something stuck in there making it rattle?

 

yes, but it does come on with the heater aswell. If the computer reads that the added resistance of turning the serpentine belt for the heater is increasing temp, it will kick on. If I start mine cold and the heater is on, within 10 seconds the fan will kick in

 

Does it only make the noise when heater is on. If so I would change it out ,don't take the chance lime I did .

 

Sounds like he is talking about the cooling fan like behind the radiator and not the HVAC blower unit. I have the same issue at idle where something is cycling on and off with the serpentine belt. I have heard it can be the AC compressor even if the AC isn't on??

 

Sometimes after mine sits for a couple of days, the heater blower motor will squeak or squall for about 15 secs before quietening down.

It does it worse in damp/humid weather.

It's been doing this for as long as I've had it, about 2 years. Think it's fixing to catch on fire?

 

basically if you have a sound like this or similar. replace it. lol (this was mine)

http://www.youtube.com/watch?v=http:...?v=TUc25nZlcMw

 

basically what happens is, when the blower motor starts to wear out it causes more drag and more electrical voltage is required to operate it. If you check the salvage yard I bet you most cherokees will have a slightly melted switch (on the back side) for the extra current draw.