Actuator Diagnosis - Electronic Touch Climate Control

Perform ``Functional Tests'' prior to performing any diagnostic procedures.
1. After determining that malfunction in mode system exists, use air flow to locate which actuator is source of malfunction. Check electrical connection to affected actuator for corrosion and/or faulty wiring. Correct as needed.
2. Recheck isolation of actuator to be sure proper unit is being tested. Observe actuator after touching LED, or through mode change. Flashing mode light indicates power to malfunctioning actuator has been shut "OFF." Touching flashing LED will reapply power for 20 seconds. Actuator should stop at incorrect position, stop at correct position with mode door not properly sealed, or remain inoperative. Using substitute known good actuators to test circuit function is desirable if such units are available. As actuators are used in specific installations, they should not be interchanged with units of different types (for example, mode door actuator may only be interchanged with identical type of mode door actuator).
Proceed to step 3 for testing inoperative actuator. Proceed to step 8 for testing actuator stopping at incorrect position. Proceed to step 9 for actuator correctly positioned with door not properly sealed.

Fig. 1 Actuator terminal identification (Typical):

3. Perform diagnosis for inoperative actuator with ignition "ON" and mode light flashing. Attach a suitable voltmeter to actuator pin C, Fig. 1, and to ground, using an inspection mirror to observe contacts. Measure voltage. If reading is 8 or more volts, proceed to step 5. If reading is less than 2 volts, proceed to step 6. If reading is between 2 and 8 volts, proceed to step 4.
4. With voltage reading of between 2 and 8 volts, perform the following:
a. Check for faulty connections between battery and fuse block, fuse block and pin B of 22 pin control panel connection, pin C at control panel connection and at actuator.
b. Check control panel for faulty diode.
c. After ensuring all connections are clean and correct, measure voltage at 22 pin connector, pins B and C. If difference between two readings exceeds 1 volt, diode is defective, requiring control panel replacement.
d. If voltage reading in step C is less than 1 volt but reading at pin B is less than 8 volts, check battery charge level and perform necessary charging system corrections.
e. If voltage difference is within service limits, but reading at pin C is less than 8 volts, control panel must be replaced.
5. With voltage reading of more than 8 volts, perform following subroutines:
a. Attach voltmeter to pin A and pin C of actuator. Touch flashing LED and observe voltage reading. (LED should remain lit for 20 seconds after it is touched. If malfunction occurs, perform control panel and actuator functional tests again to locate fault). If voltage reading is 8 volts or more, check for obstruction of linkage and mode doors, or stripped actuator gears.
b. If no obstructions are present or actuator gears are stripped, replace actuator unit. Prior to installing new actuator, any jamming, blockage, or improper operation of doors or linkage must be eliminated. Control unit should be stopping power flow whenever malfunctions occur. In certain cases, actuators without stripped gears may have to be replaced during this step if no other faults are present.
c. If indicated voltage is less than 2 volts, proceed to step 7.
6. If less than 2 volts is indicated in step 2, attach voltmeter to 22 pin connector at pin C (actuator hot lead). If 8 or more volts is measured, wire from pin C to actuator is defective. Correct as needed. If less than 2 volts is indicated, control panel must be replaced.
7. If less than 2 volts is indicated in step 5c, attach voltmeter to 22 pin connector at pin C and at actuator terminal A. Touch flashing LED and observe voltage (during power supply cycling). If 8 or more volts is measured, check continuity of actuator lead. If less than 2 volts is measured, control panel must be replaced.
8. Perform diagnosis for actuator stopping at incorrect position with ignition "ON" and mode light flashing. Attach voltmeter to pin A and pin D of actuator. Touch flashing LED and observe voltage. Cycling voltage should measure between 11 and 5 volts for actuators, except three position defrost actuators (11, 5, and 4 volts).
a. If voltage falls within specification, check continuity of pin C actuator to 22 pin connector lead. If continuity is good, replace actuator.
b. If no voltage change is indicated, replace actuator.
c. If indicated voltages are not within specification, replace control panel.
9. If actuator stops in correct position, but door does not seal properly, check door link attachment, and actuator to assembly connection. Correct as needed. Check to see that actuator arm is in correct position for control panel setting, and adjust if needed.
10. Perform diagnosis for motor running longer than 15-20 seconds with ignition "OFF," using self-powered test lamp. Connect test lamp to pin A in actuator connector (with connector removed from actuator) and to ground.
a. Check circuit. If test lamp does not light, go to step b. If test lamp lights, short circuit is present in harness. Repair as needed.
b. Using test lamp, check continuity from actuator pin D to 22 pin connector, following harness color coding. If test lamp lights, replace actuator. If test lamp does not light, harness lead is defective. Repair as necessary.