Jim Grant's Tech Tips
‘90 Cadillac Brougham, No-Stop Blower Motor
Q: My ‘90 Cadillac Brougham air conditioner control will not turn off even when the ignition is turned to the off position; consequently, the battery is run down. What could cause this problem? Is there some relay that is stuck or will a new fuse correct this problem? The AAA Service Technician advised that it might be the Blower Motor Module (A Relay System Part). I am retired and attempting to save on the repairs--the local Cadillac dealership repairs are very expensive.
- Patricia Cheavers
A: It is possible that the Electronic Climate Control (ECC) Power Module has failed and is keeping the blower motor up and running when the car is turned off. Before jumping the gun I would suggest pulling the 20 amp STOP-HAZ in the fuse panel. This fuse provides power at all times to the Electronic Climate Control (ECC) Head, (even though it doesn’t tell you that) which controls the ECC Power Module. It’s just one computer chatting with another. Removing that fuse and having the ignition (key) in the off position should eliminate any possibility of the ECC Head commanding the ECC Power Module to turn the blower fan on. If removing this fuse and having the ignition off doesn’t create a change than it is likely that the ECC Power Module has a problem. The ECC Power Module has battery power at all times and has a fusible link instead of a removable fuse. So, if the module is getting weird it can keep the climate control system, mainly the blower motor running even with the key off. The ECC Power Module is nothing special to look at. It is a piece of plastic with 4 wires in one connector. You’ll find it mounted on the firewall side (engine compartment) of the heater box. If I’m not mistaken there are only 2 screws that hold it in place and it takes about 2 minutes to change. You want to be sure that the power module is the problem, because they’re pricey and you can’t return them after it has been installed.