I have a 98 k 1500 the temp coming out of the heater is always hot even when I turn the temp down to make cooler any sugg thanks charly

 

I had that same problem with my oldsmobile Delta 88 and Buick Century.
Currently my silverados heater works great, but no such luck for the AC.
I believe the problem lies in either the temp control unit, or it is the compressor clutch.

 

I know about the air blowing out of the bottom when I turn the het on temp contol on red heat comes out even out of the vent when I turn the temp down to the blue cooler the air is hot. I turn the ac on still blows hot air but the comp comes on Thanks

 

Hi 98K,

Welcome to the Chevy Forums.

Sounds like you have a bad valve on your heater hose, which isn't shutting, or a malfunctioning climate control unit in your dash which isn't operating your heater control valve.

Look at the heater hoses under your hood first. There should be a 3/4 and a 5/8
heater hose going into your firewall. The larger of the two hoses(3/4) should have a control mechanism in the line. Is it properly connected?

 

Every thing under the hood looks okay the 2 hoses go to the motor no control yes it is funny situation I left it on the cool side all summer when temp started getting cooler I turned the heat on. The other day outside temp was warmer so turned the temp down on the inide of the truck and no cool air I was wondering if the temp control is bad or is there a way I can jump it out or do I have to replace the whole unit

 

i had a similar problem, so what i did was install a little ball valve in-line and i turn it off when it is hot out

 

where would the bad valve be not under the hood

 

It depends. If it's the inlet valve for the heater core, then it's most likely on the 3/4 heater line, under the hood, near to the firewall on the passenger side.

If it's the Climate Control Unit, that's on your dash.