Honda Acura NSX 1991 Service Manual page 925

From page 22-36
Check for continuity between the
wire(s) and body ground.
N O
Test the vent door control motor
at the heater (page 22-W.
Y E S
Substitute a known-good control
unit and recheck. If symptom/in-
dication goes away, replace the
original control unit.
Repair short in the GRNIRED,
wire(s) be-
tween the vent door control mo-
tor and control unit.
Replace the vent door control
motor.