The heating/AC fan only runs on the highest setting on my 2000 Chevy Venture. My 1998 Olds Silhouette (sp?) ran all speeds but high. The fuse box has a seperate circuit for heating/AC fan high vs. the...
There are two types of blower fan speed control. One uses a rheostat, and the other one uses electronic circuits. The speed control is atually located on the blower fan housing. It is fastened with two screws. The rheostat kind uses nicrhome wires(same wire used for heating element such as a toaster etc. The more wire wound around the mica material( anyways a mica is a heatproof material), the greater the resistance and therefore the slowe the motor will turn. The electronic kind uses a transistor, and works very much like the speed control on a cordless power drill. The transistor gets pulse from another electronic device and this pulse is modulated by the control knob in your dash. When this transistor gets messed up it gets shorted. This results in having high speed at all settings. The rheostat kind mess up when the nichrome wire gets burnt out and you end up with may a fan that works only on high, or maybe wroks only on medium and high vice versa. So the problem is the speed control mounted on your blower fan housing. If you want to know how to test them let me knw I will show you.
Aug 12, 2009 |
Chevrolet Venture Cars & Trucks