Hey guys I;m having a problem with my defrost setting on the Blazer. It works fine on the heater setting, but when i engage the defrost setting it blows the fuse. The blower motor is brand new so i know that it is not drawing too much amprage. I was wondering if anyone has had the same problem or if anyone has any suggestions.

Thanks a lot

 

From your username, it would appear that you have a '90 K5. I assume that you also have A/C. There may be a short in the wiring to the evaporator pressure control switch and/or the wiring from the evaporator pressure control switch to the A/C compressor clutch. When in defrost, the A/C compressor will run to help pull moisture out of the air for faster defrosting of the windshield.

 

thanks alot it was the conection point between the compressor and the lead.

 

Glad you found it and glad to have helped!