Heater control issues

[Crazywelder72]

I have 02 tahoe and it has the heater control with the auto feature. Anyhow if it's set all the way to cold, cold comes out but if I turn it 1 click above cold.... Hot air trickles out.

I can't make any type of warm air at all.

Need help diagnosing it please.

 

[dave/angie]

I was thinking that there was a "servo" motor that controls the hot/cold mix. You can buy, an aftermarket one, but I have been told that if you install it yourself, the first time that you turn the key on it will ruin it unless it is "zero-ed" first. Those pieces aren't that cheap and I would recommend taking it to someone who knows what they're doing.....

 

[MO Viet Vet]

There is some you tube videos about refurbishing these things but I would lean toward maybe a BCM problem. Have you had the battery go dead or unhooked lately? If so the BCM has a nasty habit of needing reset by a scanner. Dealer reset usually unless you know a friend with one or a shop with one. The scanner can be different for the BCM and the PCM.