No heat stuck on defrost. New here and need some knowledge

[buddhacardovo]

So I'm brand new around these parts and need some help. I have looked just about everywhere for the answer and can't come up with it

I have a 98 yukon. The engine heats up to normal operating temperature. The fan speed control works fine. But it is stuck on defrost and the temperature does not switch from cold to hot. I have checked the fuse block and pulled the hvac head unit to see if either were the problem but everything looked fine. My friend told me about a relay that could be an issue

Where do i go from here. I'm in Wyoming and winter is coming.

Thanks in advance

 

[someotherguy]

Most likely what you have is a failed controller. Pretty common to happen on 1995-up. You've got multiple failures there so it's not like you simply have an actuator stuck or bad.

Richard

 

[buddhacardovo]

By controller do you mean the hvac head unit with the speed select temp select and defrost to feet air?