No Heat

4cfed said:

I'm having the same issue in my wife's 98 expy. but the weird thing is the knob turns hard about halfway to 3/4 way to hot..

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Assuming this is manual controls, this developed on my 99. The temp control would be hard to turn to the point it split the back of the knob where the shaft inserted. I bought a replacement "pot" and knob, removed the control panel from the dash and changed it. The "temp." and "fan" have electrical connectors and the "function" switch (A/C , Vent, Off, Heat, Def) is vacuum.

Also, sometime during the 99 production, the color of the indicator "dot" on the knob changed from green to blue. So the build date of the truck was needed to get the right color.

Anything else on this issue? My '01 with ACC will warm right up and blow hot front and rear until it gets about to the set temp. Then the heat level and fan speed drop, but the heat level drops too far so the fan comes on high again to warm the car up but the heat level stays cool or lukewarm (not cold). If I turn the temp WAY up it'll blow hot again, but turning back to 74-ish it blows cool even though it's gotten plenty cool in the car by then and should be blowing hot. Doesn't do it every time but most. Front and rear blow the same temp. Definitley sounded like a coolant flow issue to me but checked it very well last winter and it was flowing fine everywhere it should be. Mildly frustrating with winter near again, especially since everything else on this truck works great.

Must be a common issue... I just changed the thermostat on mine with zero improvement. Temp gauge barely gets above cold. Wondering if a coolant flush is needed... I really don't feel like chasing blend door, heater core, HVAC issues, but it's getting cold up here in Northern Indiana and I have got to get some heat soon.

Braadjonesbass said:

Must be a common issue... I just changed the thermostat on mine with zero improvement. Temp gauge barely gets above cold. Wondering if a coolant flush is needed... I really don't feel like chasing blend door, heater core, HVAC issues, but it's getting cold up here in Northern Indiana and I have got to get some heat soon.

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Hmmm...even though you just changed it, it sounds exactly like your 'stat is stuck open. Not much else that will make your engine run cold.

Braadjonesbass said:

Must be a common issue... I just changed the thermostat on mine with zero improvement. Temp gauge barely gets above cold. Wondering if a coolant flush is needed... I really don't feel like chasing blend door, heater core, HVAC issues, but it's getting cold up here in Northern Indiana and I have got to get some heat soon.

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Put a scanner on it (even it is just torque on a droid phone) and see what the ECT is reading.

Can anyone provide insight on my no heat issue where I get a decent amount of heat at higher RPMs but no heat at all at idle?

Thanks,
~ Dan

Welcome to the site.

Search the heating / cooling section since this is a common problem with these vehicles and we always repeat what is in the older posts.