Heater Blowing cold at any temp

[coach3rd]

Anyone have or seen this problem with the heater set to 90 and blowing cold. I have had this in the shop for this before and they say the flap for outside is not closing properly but I would like a permanent fix. They take off the dash and close the door?

[coach3rd]

Anyone have or seen this problem with the heater set to 90 and blowing cold. I have had this in the shop for this before and they say the flap for outside is not closing properly but I would like a permanent fix. They take off the dash and close the door?

[dochummer]

Have you tried running the heater with the engine on? j/k Never heard of the problem...sorry, can't help...

[KenP]

I had something similar happen on another
gm product. It was an issue with the vacuum which caused the blower to put out ONLY hot air.

Take your truck to Great Neck RD heading north over the bridge. Go fast. When you get to the top, take your foot off the gas and coast all the way to the light. Your truck will pull vacuum and may fix the problem.

I know it sounds wierd, but it worked for me on the old Tahoe.

[intimidator]

you have a faulty temperature door actuator. take it to the dealer if you have a warranty. and make sure they recalibrate the hvac doors.

[kodiakz]

I have the exact same problem. Mine is intermittent, but if I have the heater set to anything less than 90 it only blows cold air. Oh well, the warranty list continues to grow!!!

[Ed G.]

With the heater running try pressing the a/c button. This should show the a/c icon with an x through it. Worked for me.

Ed