Monaco V6-182 3.0L SOHC (1990)
Air Door Actuator / Motor: Customer Interest
Heater & A/C - No Heat/No Cooling
Models
1990 BB Body
Subject
Service Manual Supplement - Blend Air Door Motor Diagnostics
Index
CLIMATE CONTROL
Date
March 12, 1990
No.
24-01-90
(C24-02-0)
P-660
BODY CODE LEGEND
BB - DODGE MONACO
SYMPTOM/CONDITION
The customer may complain of "not heating" or "not cooling" depending on the ambient temperature. The discharge air coming from the climate control
system does not change in response to changes in the temperature setting.
DIAGNOSIS PROCEDURE
The no heating or no cooling condition listed above may be caused by a malfunctioning blend air door or a problem with the blend air door motor.
The procedure for diagnosing the semi-automatic climate control blend air door system has been expanded to make it more accurate and easier to
understand. It is important to use the following diagnostic procedure along with the service manual before replacing the blend air door motor.
NOTE:
When diagnosing the blend air door motor, the motor must be attached to the blend air door. Use only the on-board air control module
(ACM) computer diagnostics when diagnosing problems with the blend air door motor. Do not use jumper wires when diagnosing this
system. Failure to follow this procedure will cause the potentiometer inside the motor to lose "registry" with the air control module and
also lose reference with the blend air door. The air control module then will not be able to determine the position of the blend air door.
1.
To enter the diagnostic mode, turn the ignition key to the run position. Locate the A/C switch pod on the right side of the
steering wheel and press the "blower speed switch up arrow", the "select switch left arrow" and the "front defrost switch" all
simultaneously for three seconds. After holding the switches for three seconds, all the mode indicators, all the blower speed
indicators and the temperature digits on the climate control display should illuminate. When the switches are released, the
low blower speed indicator will flash indicating the system is in the diagnostic mode "LO".
2.
The blend air motor is diagnosed in diagnostic mode "M2". To get to this "M2" mode from the "Lo" mode, press the "blower
speed switch up arrow" two times. The first time the "blower speed switch up arrow" is pressed, the system will be in
diagnostics mode "M1". Pressing the "blower speed switch up arrow" a second time puts the system into diagnostic mode
"M2". When this is done, the Low, Medium-Low and Medium-High blower speed indicators will flash indicating the system
is in diagnostic mode "M2".
3.
Also at this time, the BI-LEVEL indicator will flash every one-half second indicating the blend air door motor is positioning
the blend air door. When the BI-LEVEL indicator stops flashing and stays illuminated, the blend air door motor will have
positioned the blend air door according to the temperature setting which was displayed prior to entering the diagnostic testing
mode. At this time, the blend air motor potentiometer voltage will be displayed in the temperature digit box. Depending on
the temperature selected prior to diagnostics, the actual voltage will be between 1.2 volts and 4.0 volts (+ or - 0.3 volt) but
since this is a potentiometer, the voltage digits will read between 12 and 40 (+ or -3). You must mentally put a decimal
between the digits to read the actual voltage.
