The doors all open from defrost and heat but I have no fan. I'm sure it is something simple I hope.
How do I check My fan and fuses for my heat on 2000 Cadillac Eldorado
Chances are the blower motor has failed on your 2000 Cadillac Eldorado. The simplest way to check is to plug in a new blower motor and see if it works. You may need to lower the front of the engine cradle to allow removal of the old blower motor.