HVAC Controls send serial comms message to BCM, Then BCM send serial comms message to ECM, then ECM commands the A/C relay on, if all other parameters are good.
Refidgerant
Engine Speed
Coolant Temp
etc.
I can't thank you enough for all the information you provide!!!! Thanks again. The so called A/C specialist told me that the ECM maybe fried.
The best I can do, is to check for codes to narrow the issue. Thanks again!