2002 Cadillac STS internal heater blower

Do you mean the "Auxilary blower motor"? Here's the procedure for removal. Installation is the reverse.

Remove the center console.
Disconnect the rear blower motor assembly electrical connectors.
Disconnect the air ducts from the rear blower motor.
Remove the rear blower motor retaining bracket nuts.
Remove the bolts retaining the rear blower bracket to the IP.
Remove the rear blower motor retaining bracket studs.
Remove the rear blower motor insulator from under the rear blower motor assembly.
Push the rear blower motor assembly down.
Push the rear blower motor assembly forward in order to disengage the rear air duct.
Remove the rear blower motor assembly from the passenger side of console.