Chevrolet Repair: 2003 tahoe Z71, powertrain control module, body control module

Question
Hello, I have a 2003 Z71 and when I turn the truck off the blower stays on for at least 10 minutes before it goes off. When turn the truck on in the morning the blower does not come on until 10 to 20 minutes later. What could be the problem. FYI... i did take it to the dealer and they mentioned that I should have the BCM replaced. I have already had the PCM replaced.... What could this be?????

Answer
Hi Don Harris,

The PCM is Powertrain Control Module

The BCM is Body Control Module

The BCM is responsible for radio, windows, seats, blower and climate control, compass, auto-dim mirrors, theft control, anything else the body of the car does.  

The PCM is responsible for motor and trans operation.  These two computer do communicate with eachother (ie. the theft control tells the ECM it is ok to start the car).  

It is possible the BCM is telling the blower to run for some oddball reason.  The dealer is not always right, but a scan tool with capibility to tell you more than codes is needed to verify.  Unfortunately the only mechanics with that $2000+ scan tool is dealer ones.  

Hope this helps.

C J S