Hello all, i have a 2005 Chevy express 2500 cargo van. I have an issue with my AC/ABS system. My Ac and heater controls work on high speed only, can change temp, can change to every direction just can not change fan speed with out the amber abs light flashing and warning sound going off. It only does this when you change the fan speed off of the high position. The air works well on the high position but does not work at all at any other speed. I replaced the blower motor resistor last year, I removed the ground wires and cleaned them and the mating surfaces making sure there is good contact. There are no active or stored codes. I’m not sure where to go from here. Any and all help is greatly appreciated!

 

Does the fan spin on the lower speeds? What replacement blower motor resistor did you use?

 

No, if does not work on the lower fan speeds, only high speed fan. I’m not exactly sure what blower motor resistor it was. I called the local gm/Chevy dealership and gave them my vin and just got it from them.

 

Sounds like you got the OEM blower motor resistor then.

I would try checking resistance for all the leads on the blower motor resistor to confirm it's still good.

 

If the blower motor is worn out, it will keep blowing the resistors.

 

if it’s the blower motor wouldn’t it not work at all?

 

No, not necessarily. Motors can have very high internal resistance when they start going bad. This means they are drawing very high amperage. That high amperage will heat up and even blow your resistors. Keep in mind, Hi is the only speed the fan does not use any of the resistors to operate so that’s why it is the only speed that works.