K: A/C SUNLOAD SENSOR INOPERATIVE

PINPOINT TEST K: A/C SUNLOAD SENSOR INOPERATIVE

K1 PERFORM EATC SELF DIAGNOSTICS TEST

- Turn the ignition switch to RUN.
- Press OFF and FLOOR buttons simultaneously and then press AUTOMATIC button within two seconds.
- Self test may run as long as 30 seconds.
- After self test, record all error codes.
- Press the blue (cooler) button to exit self test.

- Is error code 050, sunload sensor shorted, displayed?

- Yes
Go to K3.

- No
Go to K2.

K2 CHECK FOR INTERMITTENT SHORT CIRCUIT

- Upon completion of self test in HI, was error code 052 displayed?

- Yes
Go to K6.

- No
Go to K4.

K3 CHECK SUNLOAD SENSOR RESISTANCE

- Disconnect battery ground cable.
- Disconnect sunload sensor wire harness connector.
- Using a DVOM, check the resistance across the two sensor connectors.

NOTE: The A/C sunload sensor is a photovoltaic cell and should have some unspecified resistance across the terminals depending on the light available to the sensor. The only test that can be performed without specialized equipment is for a short. If the resistance across the sensor terminals is zero ohms, the sensor is shorted and should be replaced.

- Is there zero resistance?

- Yes
Replace shorted A/C sunload sensor. Restore vehicle. Go to K1.

- No
Go to K4.

K4 CHECK CIRCUIT 468 (BR) AT SENSOR CONNECTOR

- Turn ignition switch to the RUN position.
- Turn EATC module to NORM A/C position.
- Partially remove EATC module as outlined.
- Gain access to the A/C sun load sensor as outlined. Disconnect A/C sunload sensor.
- Using voltmeter, check Circuit 468 (BR) for voltage at A/C sunload sensor connector.

- Is voltage 5 volts?

- Yes
Go to K7.

- No
Go to K5.

K5 CHECK CIRCUIT 468 (BR) AT EATC MODULE

- Using voltmeter, check Circuit 468 (BR) at EATC module Pin 16 for voltage.

- Is voltage 5 volts?

- Yes
Go to K6.

- No
Replace EATC module. Restore vehicle. Retest system.

K6 CHECK CIRCUIT 468 (BR) FOR OPEN

- Turn ignition switch to the OFF position.
- Using a jumper connected to a known good ground, connect other end to Circuit 468 (BR) at sensor connector.
- Using an ohmmeter connected to a known good ground, connect second lead to Circuit 468 (BR) at EATC module connector Pin 16.
- Measure resistance.

NOTE: An open circuit in the wire harness will appear to the EATC control assembly as no sun.

- Is resistance 5 ohms or less?

- Yes
Go to K7.

- No
Service Circuit 468 (BR) for open. Restore vehicle. Retest system.

K7 CHECK CIRCUIT 476 (BR/Y) RESISTANCE

- Connect jumper to Circuit 476 (BR/Y) at sensor connector.
- Using an ohmmeter connected to a known good ground, connect second lead to Circuit 476 (BR/Y) at module connector Pin 3.
- Measure resistance.

NOTE: An open circuit in the wire harness will appear to the EATC control assembly as no sun.

- Is resistance 5 ohms or less?

- Yes
Replace A/C sunload sensor. Restore vehicle. Retest system.

- No
Service Circuit 476 (BR/Y) for open. Restore vehicle. Retest system.