2000 Jimmy Heat is always on

milber2

We have a 2000 Jimmy and the heat stays on all the time. Yes the heat control is turned to minimum.GM says that is a normal condition for the heater core to dissipate excess heat from the cooling system all the time, that is pure crap. I've owned 12 vehicles in my life time and only had one do that before, stuck control valve. Couldn't spot one in the engine compartment. Maybe GM is too lazy to check under the dash. Anyone had the same problem and get the run around from GM? Did you get it fixed?

jgmilberg

They need to check the blend door operation. Gm has found that stagnant coolant in the heater core will cause premature failure, so now they use a door on the heat/cool box under the dash to control the heat. If your heater will not turn off then the door acruator is stuck or the door is jammed.

Here is some info from the manual:

Heat Excessive

The most likely cause of excessive heat from the heater system is a bad air temperature actuator. Other related causes of excessive heat include a faulty mode selector (control assembly), or an open or
shorted electrical harness.

joe3891

When everything is turned off i get floor heat in my 99 Sonoma same system as the Jimmy.I have seen a lot of posts on the problem but no actual fixes posted.I going to the dealer this spring before my warranty runs out,it should really be bad by then.

swschrad

how about taking it back to the dealer now? the screw or glue gob or warped plastic part.. .or bad actuator, loose control hose, or bad control... aren't going to get any better with time. lot of ways these doors can get hung, and it's a royal pain to hink around with the things. might as well allow time for some misfires in the process.

joe3891

is my rule before I bring it in for warranty service,I want it to worth the trip.

heng

My dealer said its normal for Jimmy's. A friend with a Blazer got the same response.

So be prepared to be firm with the dealer. Otherwise you won't get any resolution.