2000 GMC 1500 Pick-up heat problems.

[788tj]

I have a problem with the temperature adjustment knob. When I run the truck long enough to get it up to operating temp 210 degrees and I have the temp knob for the indoor air on the hot setting then the inside gets hot so I turn the knob to the cool setting but all I get is hot air. Tha other knob works fine as far as adjusting from toes to def and vent the air just remains hot almost like the vavle will not stop the coolant from circulating through the heater core. Is this a vacume operated system and Where are the system parts located? It is an extended cab with two full doors and two half doors and bucket seats with a center councel. Any info would be greatly appreciated.

 

[Reel Poor]

Re: 2000 GMC 1500 Pick-up heat problems.

It sounds like a blend door motor operational problem. It will most likely require a qualified technical service person to do the proper diagnostics.

 

[Bob_VT]

Re: 2000 GMC 1500 Pick-up heat problems.

I agree with RP. A great deal of the blend door problems are normally caused by a rodent nest. I have seen ton's of hay, grass, wood shavings pulled from the inside of heater vents. It is best to get it to a dealer or a local mechanic.... or purchase a manual.<br /><br />Bob

 

[DJ]

Re: 2000 GMC 1500 Pick-up heat problems.

As stated-BLEND DOOR.<br /><br />Could be a nest, could be a vacuum line off, or leaking door diaphragm leak.

 

[fire831]

Re: 2000 GMC 1500 Pick-up heat problems.

A buddy of mine has the same truck and it does the same thing. Still don't know why but when I changed the in cab air filter on my 2002 with 50,000 miles on it,I could not believe how dirty the filter was. Don't know if this is a possible cause or not but we were thinking about changing his to see if it helps since his filter has never been changed and has 150,000 miles. This may not have any thing to do with the problem but I did notice a change in airflow on my truck after I changed the filters.

 

[Moody Blue]

Re: 2000 GMC 1500 Pick-up heat problems.

Not the same problem but similar. On my 98 Safari van I was unable to shift the air from floor to defrost to vent etc. Thought it was the vacuum operated actuator. Tore half the dash apart only to find I was not getting any vacuum to it. Turned out to be a split rubber vacuum hose off the intake manifold.