The blower motor started to only work on the high setting, 4, all other settings, 1,2,3, were not working, I thought the blower control switch may have been bad. I checked with the dealer, the part to replace the switch is the whole control panel, $200. I wanted to make sure that was the problem before spending the money. I checked on the internet and found this is a common problem with Colorado's. it turns out that the blower motor resistor block and connector are suspect. I did in fact check this out and found evidence of over heating on the connector. I can get the fan control to work properly by moving the wires on the connector to the resistor block. I think this is a safety concern due to the fact that others have reported the connector actually being melted from over heating. GM does not have any service bulletins or recalls out for this issue. On the internet search there was additional information concerning the grounding block in the engine compartment that has led to several electrical problems. I also found my grounding block to have had some corrosion build up that may have caused problems with my electrical system. My passenger side power window was intermittent. I cleaned the corrosion on the grounding block and everything is working properly.

- Shalimar, FL, USA