Ive got a 2000 Jimmy SLT with computer climate control. I am only getting heat when I have the temp **** on the "red" setting which Im assuming is "max heat". There is no temp change when I toggle through the temperature settings (ie 66, 70, etc). The heat blows steaming hot when it is on the hot setting, and both heater core lines are very hot when I checked them.
Ive read through some old threads on similar problems and tried the re-calibrate procedure of the blend door by removing the RDO fuses and the HVAC fuses, but it doesnt seem to do anything for me. I also pulled the blend door actuator off and verified taht it is moving correctly when i rotate the temp switch and it seems to be.
Any suggestions? could it be the thermocouple for the cabin temperature has gon bad? or could it be the computer climate control module in the dash itself? Also, sometimes there is a strange "humming noise" coming from the dash, sounds like it could be coming from the climate control module, but this noise is only intermittent.
Any help greatly appreciated. Thanks.

 

So it always pumps heat out regardless of the temperature setting? Sounds like the control module may be fubar'd

 

It does not always pump out heat, it only puts out heat when it is on the highest setting. When it is on anything but the highest setting it feels like it is just at ambient temp (when the a/c is off of course).

 

I have a computer climate control thingamabob, from my parted out 98 Jimmy, for sale. Let the bidding begin!

 

I have the same thing going on with a 99 Blazer. Figured that it was the contral panel, since it apparently has the controls and a control board inside. Paid $90 plus $8 shipping for a used one. I WISH that I could say that it fixed the problem, but nope. I've tried the re-calibrate option too many times to count.[:@] It looks like getting inside the dash to look at other items will not be a fun thing to do, but will be attmepting it this weekend.

BTW - forgot to mention. Mine was working great, until I had to replace a dead battery, so you'd have thought that the re-cal procedure would have been all that was required.