Heater blower not working no fan no ac no defrost or heat how do I fix it
Myself on 1998 Cadillac DeVille

where is it located and what else could have caused this problem

1 answer
The blower motor itself is probably the problem. Check the fuses first to make sure one isn't burnt out. Here's the process for removing the blower motor: http://www.ehow.com/how_6463767_install-1998-cadillac-blower-motor.html