I have a 2004 Blazer, while driving to get groceries I noticed the vehicle was not getting up to temp. So I'm thinking thermostat stuck open, however when this was going on my heat didnt turn on at all. Blower motor didnt kick on at any speeds. Kept messing with the dial and then the motor kicked on the car finally got up to temp. Any suggestions?

 

You can do most of the testing at the blower relay socket contacts with the relay removed. This way you don't have to open any wire harness bundles and probe wires. If the blower dies again, first swap the relay with a known good relay. If that does not work then grab a DVM and report back so I can walk you through the debug process in the relay socket.




George