Test I

PINPOINT TEST I: INSUFFICIENT, ERRATIC OR NO HEAT

Test I1:

Test I2-I4:

Test I5-I7:

Test I8:

Normal Operation
Under normal operation, the Automatic Temperature Control (ATC) solenoid and manifold receives a ground from the Dual Automatic Temperature Control (DATC) module through circuit 1070 (BN/LB). When the heater control valve vacuum solenoid is to be energized, the ATC solenoid and manifold receives power from the DATC module through circuit 1069 (OG/LB).

Possible Causes
- An open, short to voltage, ground in circuit 1069 (OG/LB).
- ATC solenoid and manifold.
- DATC module.
- Heater control valve.
- Stuck or bound linkage or door.
- Leaking or plugged vacuum hose.
- Temperature blend door actuator.