DTC 3 - Blend/Passenger Actuator Did Not Reach Cold Stop

DIAGNOSTIC TROUBLE CODE 3 - BLEND/PASSENGER ACTUATOR DID NOT REACH "COLD" STOP
When the HVAC Control Module calibrates the Blend/Passenger Door Actuator, it moves the actuator toward the HOT position and then toward the COOL position. In the COOL position, circuit C36 of the 21 pin connector should have a value of approximately 0.6 to 1.2 volts. When the actuator does not reach the COOL position, DTC 3 sets.

Detection
When the voltage at C36 is greater than 2.0 volts, the DRB III will display the DTC.

Possible Causes
- Blend/Passenger Door reaches the COOL position and does not respond to changes in control panel settings,.
- Blend/Passenger Feedback Signal circuit is SHORTED to 5 volts.
- Blend/Passenger Actuator is stuck.
- Blend/Passenger Door is stuck.
- Blend/Passenger Door Actuator Driver circuit is OPEN.
- Blend/Passenger Door Actuator Drover circuit is SHORTED to ground. Diagnostics begin momentarily and then STOP with NO LED's until the short is removed, and then both WIPE and INTERMITTENT LED's flash simultaneously.
- Battery Voltage is less than 10.0 volts.

If there is air flow (passenger side on Zone control),, even though the DTC indicates that the actuator cannot reach the cool position, there is a short to voltage in the Blend/Passenger Door Feedback Signal circuit (the door is moved to the Cool position, attempting to decrease the feedback voltage).

If the Blend/Passenger actuator fails in the Mid position, both DTC's 3 and 4 will be set.

If the Blend/Passenger Door/Actuator fails in the Hot position and is blowing hot air, DTC 3 is set.

Test Procedures
1. Check if the correct HVAC control module was used.
Disconnect the Actuator connector.
2. Using a voltmeter, measure between pins 1 and 5. If the voltage is not 12 volts ± 1 volt, check the actuator driver circuits wiring for a short or open circuit. Measure the voltage between pins 2 and 4. If the voltage is less than 4 volts, check the 5 volt supply circuit. Measure the voltage between pins 3 and 4. If the voltage is less than 4.5 volts, check the actuator feedback circuit.
3. Remove actuator, and check if gear pins are in the correct cam track or binding. If OK, go to Step 4. If not OK, repair as necessary.
4. Check for binding door, if door is binding repair as necessary. If gears and door are OK, replace actuator.
5. Once repairs are completed repeat the Calibration Diagnostic and Cooldown test. Repeating the test is necessary to clear the fault codes.