I have been working on my dad's 99 Silverado. He had an issue where the blowers would only blow hot air. After checking refrigerant and making sure that there wasn't a problem with the AC unit, I decided to replace the blend door actuator. Once I removed the actuator, I could flip the blend door back and forth and confirmed that there was an issue with the actuator and not the AC system. The problem is, once I replaced it, it hasn't fixed the issue and in some ways I am stuck. When I plugged it in and turned it on, I could see the actuator move a little, I was assuming to calibrate. I tried moving the temp control between hot and cold, and the actuator does not move. The problem I now have is that I can't even install it it to just blow cold air, we live in TX, because the blend door post does not line up with the opening in the actuator. Any ideas on what else the problem could be? I have checked the fuses in the relay box and all look good. Is there any connection under the dash or another location for a fuse that might be causing the issue? Any help would be appreciated.

 

Which blend door did you change? Also have you changed the in-cab air filter?

 

It is the blend door below at the very bottom of the dash near the floor. It handles the cabin temp. This is a manual system with a dial that controls hot and cold. It is a 99, so there isn't an in-cab filter. The actuator won't respond to signals from the temp control. I have checked all of the cabin and under the hood fuses and all of them look good.

 

Did you power up the new actuator before installing it?

 

The way I powered it up was to plug it in to the wiring harness and then turn the dial to see if it moved and it did not. Is there another way to test the actuator power?

 

I had a 99 Silverado years ago and I powered up the actuator before installing it to see if it moved. That was a big mistake. Of course after installing it into place is not a problem.

 

What was the big mistake?

 

Powering up to see if the new works before installing it in place.