I just replaced a new stereo in my Colorado today. It works great, but suddenly the A/C will only work if I turn it on high. I replaced the blower motor resistor ans it still only works on high.

Can anyone tell me what I need to do next before I take it to a mechanic and get charged too much?

 

When you installed the new stereo did you have to do any rewiring or was it just plug in and not touch any of the wires? It appears that maybe a wire was relocated that should not have been touched.

 

It was just connect the mounting harness and done. I didn't have to touch any of the othe wires. I checked fuses so those are good. Any other ideas?

 

It could possibly be the speed selector switch.