I just changed the heater core on my 89 Blazer. What a pain in the a$$. I removed the dash to make the job easier, including all the gauges and switches. After getting the core and dash back on, I checked to make sure everything was working. Everything is working fine, except the fan won't kick on for the Heat and AC. I did disconnect that switch and double checked to make sure everything was hooked back up. Any clues? Thanks