Defective blower motor or blower motor resistor pack.
Because they are two separate units independent of each other.
the problem lies in the fuse, switch, motor, or wiring.
Well in my case (91) previa the connection inside f the blower housing had vibrated loose.
tested blower,ok. then tested incoming voltage to blower and found to be zero. the final step was to replace the blower switch. To replace that switch, the middle part of the dashboard, including the radio had to be removed. The ac and heater come in one piece. It worked fine then. I think, there is a chance that the switch could be just cleaned up and it would work, again I think.
When the front blower for heat and a/c work fine and the rear does not on the 2001 GMC Yukon it could be a blown fuse. Automobile manufacturers rarely have both of these blowers running off the same fuse.
Bad fuse (open), bad switch or bad blower motor.
I dont know anything about cars but my blower stopped working in my car and I took it to the mechanic and he changed a fuse and it started working again. Then a couple of months later the blower stoped blowing again and I took it back to the mechanic and he said the fuse is fine it might be the blower moter, how can I tell, I think it's a loose wire because my radio was removed and everysince my radio was removed my blower has been giving me problems.
The wiring, switch or blower has failed.
i think you need to replace the blower resistor and or relay
YOU HAVE A RESTICTION AT THE ORFICE TUBE OR EXPANSION VALVE. OR THE BLEND DOOR ARE NOT WORKING CORRECTLY. WHAT KIND OF VEHICLE - YEAR MAKE MODEL? 2007 Chevy Surburban...the a/c is working fine back and front but the front blower is blowing air very low, even on high speed?
blower resistor
I have a 96 Tahoe and mine stopped working. The most common reason is heat build up inside the blower motor switch caused a meltdown on the backside of the switch and it shorted it out completely. The dash pops off and the switch housing comes out with two screws and unplugs. It's a part you can buy at the local auto store (in my case Autozone) and it's now working again just fine. hope this helps