Jim Grant's Tech Tips
'93 Chevy Silverado, Fan Only Works on High
Q: I have a '93 Chevy Silverado and my fan only works on high, medium and slow don't work. I asked a couple of mechanics and they said that it was the blower fan resistor. Can you tell me whats wrong with my Chevy?
A: It is possible that the blower resistor is the cause for your problem, but your 93 Chevy has an interesting twist in the blower speed control that can be misleading. Depending on which ventilation system your Chevy is equipped with this oddity can throw a wrench in what would seem like simple diagnosis. Why is that? Your vehicle could be equipped with a low speed blower relay. If the low speed blower relay fails, there will not be low and medium blower speeds only high. But there maybe a quick trick to checking the low speed blower relay yourself. If Im not mistaken, the high-speed blower relay is the same as the low-speed. Look closely at the relays for matching part numbers. This means you should be able to swap the relays. If low and medium speeds return, then it is possible that all that is needed is a replacement relay. If there is no change than the blower resistor could be the cause.