B: EATC Blend Door Actuator Functional Test

B1 CHECK BLEND DOOR ACTUATOR

NOTE: Perform EATC Functional Test before proceeding.

- Disconnect both electrical connectors from rear of EATC control assembly. Drive the actuator in both directions by jumping the following pins. Ignition switch must be in RUN position.

- Pin 24 (57, BK) to Pin 22 (246, P). This drives the actuator CW - max cool.

- Pin 24 (57, BK) to Pin 21(245, BR/LG). This drives the actuator CCW - max heat.

- Does the actuator drive in both directions?

- Yes
Go to B2.

- No
Go to B3.

B2 MEASURE ACTUATOR RESISTANCE

- Using technique outlined above, set actuator to full CCW travel (max heat).

- Using any digital volt-ohmmeter, measure resistance at the following EATC control module connector pins.

- Pin 15 (436, R/LG) to Pin 6 (438, R/W) 5000-7000 ohms.
- Pin 5 (437, Y/LG) to Pin 6 (438, R/W) 3500-6000 ohms.
- Pin 5 (437, Y/LG) to Pin 15 (436, R/LG) 250-1500 ohms.

- Are all resistance measurements within the acceptable range?

- Yes
Replace EATC control module.

- No
Go to B6.

B3 CHECK ACTUATOR DRIVE WIRING

- Check vehicle wiring harness and connector continuity as shown below. Disconnect connectors from both EATC control module and blend door actuator. Use any digital volt-ohmmeter.

- EATC connector pin 21 (245, BR/LG) to actuator connector pin 1.
- EATC connector pin 22 (246, P) to actuator connector pin 5.

- Is there continuity?

- Yes
Go to B4.

- No
Service/replace wiring harness.

B4 CHECK ACTUATOR POWER

- With ignition in RUN position, check Pin 8 (640, R/Y) of actuator wiring harness connector for battery voltage.

- Is there battery voltage?

- Yes
Go to B5.

- No
Service Circuit 640 (R/Y).

B5 CHECK ACTUATOR GROUND

- Check Pin 6, Circuit 57 (BK) of actuator wiring harness connector for continuity with a known good ground.

- Is there continuity?

- Yes
Replace blend door actuator.

- No
Service Circuit 57 (BK).

B6 CHECK ACTUATOR FEEDBACK WIRING

- Check vehicle wiring harness and connector continuity as shown below. Disconnect connectors from both EATC control module and blend door actuator. Use any digital volt-ohmmeter.

- EATC connector pin 15 (436, R/LG) to actuator connector pin 4.
- EATC connector pin 5 (437, Y/LG) to actuator connector pin 3.
- EATC connector pin 6 (438, R/W) to actuator connector pin 2.

- Is there continuity?

- Yes
Replace blend door actuator.

- No
Service/replace wiring harness.