The ac/blower circuit is very marginal on these vehicles and the circut is pushed to the limit most of the time.

An older blower will make this situation worse as it tends to draw more current.

You can find the blower by lowering the passenger kick panel. It's directly over the panel and can be dropped down from that position. There is a plug directly in front of the unit. You can apply 12V and ground to the plug and see what the motor is doing, independent of the controller, resistors, and CCU.

The loss of the blower motor can be related to the controller, the resistor bank, the CCU, the motor itself, or the temperature sensor in the head.