Cadillac Repair: 1991 DeVille A/C Blower will not run, electronic climate control, automatic temperature control

Question
I have a 1991 DeVille.  The blower will not run.  The blower motor was recently replaced for this reason with a new one.  I doubled check the new blower to make sure that it works by applying power to it and it does, in fact, run with straight 12 volts applied to the connector.

Questions:
1. Is there are relay in this circuit such as one of the relays in the center of the firewall just about the blower motor?

2. Could this be a bad Automatic Temperature Control Module?

3. Could this be a bad dash panel control even though everything seems to work fine?

4. Could it be the Electronic Climate Control Module?

Where are these two modules located if one of these is the problem?  Is there a way to test them?


Answer
The fault is most likely in 90% of all cases a fault of the POWER MODULE. This is located on TOP of the large black plastic housing to the left of the blower motor while standing in front of the vehicle.  It is held in place by 3 7mm screws and when you remove it, You will know you have the correct part as you will see a large aluminum finned component on the bottom of the module.

However, It could also be the:

BCM computer or the A/C-Heater programmer.

You will need, If necessary, Electrical schematics, Test procedures and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture.  I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information.