Replaced it last Friday and everything worked fine until Monday when it went again,--blower keeps running after car is shut off...

Any ideas what is fouling the module???

Defective module? What brand did you buy? Internal break in the wiring to or from the module? Try flexing the wiring with the blower running.

Hi ...
Check this (http://www.cadillacforums.com/forums/electrical-technical-information/7691-ecc-power-module-blower.html) out.
John