Dual Climate Control - No heat passenger dash

[mcqueary]

When I use the heater I get warm air from the driver's side upper dashboard vent but cool air only from the passenger side upper dashboard vent. These are the vents near the windshield. I get warm air from the floor vent.

I ran the built-in diagnostics and got codes 41, 141, and 152. According to the service manual, codes 41 and 141 verified that the problem is the "passenger side air mix actuator circuit open, shorted, or not calibrated". The door is apparently stuck in the cold air position and will not allow heated air from the heater core to pass through. Code 152 means Keep alive memory lost. I'm not sure why I got this code.

My question is this. How difficult is it to get to the problem area? I guess I need to check for voltage to the motor, the motor itself, and possibly a mechanical jam. Are there any common problems that I can expect to find?

Again, this is a dual climate control system (CJ2) on a 1993 Lesabre Limited.

Thanks,
Tom