actually this problem is in my brother's 2000 blazer. his heater is not working. the fan doesn't even turn on. he had this problem before and we found a blown fuse. that took care of the problem. but this time we checked all the fuses and they looked fine. we tried swapping fuses anyways, but still did not cure the problem. he said that it (heating fan) has been making noise when he first starts his truck in the morning, but eventually it goes away. it has been in the single digits here in NY this week. so what might be the problem

 

bad heater core?

 

Does the fan work on all speed or is it just cold air coming out?

 

fan doesn't even work at ALL, so nothing is blowing at all

 

where in NY are ya?

 

Sounds to me like you need a new fan motor. The heater core should not keep the fan from coming on. Good indication when the fan was making noise that it was on its way to the toilet. Have you checked to verify that the motor was getting power?

 

I would say new fan motor and flush the heater core out and put in a new thermostat. I'm in amsterdam just west of albany.

 

i was thinking fan motor too. thanks guys

 

well it turned out to be the blower motor