I have an 02 2500hd with the 6.6LD. I'm not getting any heat out of the thing. My A/C is working just fine and all my fluids are good.My engine is getting up to temp like it should and I don't even get worm air out. I just flushed out my heater core with no change to the problem. I think that the ECU might be out or something. Maybe even a relay on the heater core. If any one has had this problem PLEASE HELP. Its to damn cold to be driving around with no heat.

p.s.
Sorry about the spelling there is no spell check on here.

Patrick

 

Make sure the valve is open going to the heater core. When the core was flushed were the hoses taken off the core and just the core flushed? You may have a plugged hose.

 

Not sure where the valve is to open it up. I think that it is on the firewall?? I did only take the hoses off to flush the core. Going to check the heat on the hoses today when I get her wormed up.

 

I checked the heat out of the hoses coming into the heater core. I'm not getting any heat in either hose. Not sure where to go from here. Is it possible that my thermostat is wide open?? What is the normal heat range for a Duramax 6.6L?? I let it sit and worm up this morning for about 20 min. and it got up to about 165 and after driving it to work it got around 190. That is the highest that I have gotten it. Should it be running a little hotter?? Thanks for the help.

Patrick

 

Well I have checked all of the electrical components that have to do with the ac and heater controls with no problems. Does any one now what I should do next????

 

I am having a heater problem as well. There is very little heat, so you can only feel it when the fan is on low. When the fan is on high what little heat there is dispersed to quickly. I know enough to check the engine cool but that doesn't seem to be helping so I guess I'll have to check the running engine termperature and look into the heater core.