Heating problems.

[Underdog67]

Hello. I'm hoping someone can help me with my heating problem. I get heat all the time, and no defrost. Can't change the temp, or change where the air goes. The truck isn't equipped with AC, either (FYI).

More info will be provided if needed.

Thanks for your help.

'dog.

 

[1985_K5_Silverado]

Has it always done this (and if so, how long have you had the truck), or is the constant heat a new thing?

 

[AZ79K5Project]

Check the cables and make sure they are attached to the duct work. Also, I think there is a vacuum actuated defrost but I might be wrong on that one.

I know one my vacuum lines that control a part of the duct is broken.

 

[tRustyK5]

There is a 'blend door' under the dash and the little arm that moves it is plastic and often breaks. This leaves the door nearly inoperable and open...heat all the time and no defrost. Follow the cable down to the area of the blend door.

I can't recall how much crap is in front of it, but I think it's just the lower ducting for the heat.

Rene

 

[hero]

If you are getting heat only, it is the vacuum line that controls the selector. It's not getting any vacuum at the dash. The selector part that changes between A/C, Vent, Heat, Def is controlled by vacuum. My Blazer did the same thing and I ended up running a new hose to the engine and splicing it into that connector. Was kind of a pain to do. Hopefully you can just find what vacuum hose isn't hooked up, or trace it from the heater control out to the engine.