B0490

Schematic:

CIRCUIT DESCRIPTION
The passenger temperature controls are simple momentary contact switches that connect a series of resistors so that each switch selection corresponds to a fixed resistance value. The Front Passenger Door Module (FPDM) determines which switch has been pressed by the voltage drop across the corresponding resistance value. The FPDM converts this input to a digital signal and communicates it to the Driver Door Module (DDM) over the Simple Bus Interface (SBI). The DDM is responsible for the class 2 interface and setting the DTC.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON.

CONDITIONS FOR SETTING THE DTC
^ The DDM detects that the signal circuit of the passenger HVAC switch is less than 0.09 V (5 counts) or greater than 4.90 V (250 counts).
^ The DDM detects that the passenger cooler or warmer switch is active for greater than 30 seconds.

ACTION TAKEN WHEN THE DTC SETS
The DDM will ignore the switch command.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the DDM no longer detects a failure.
^ The history DTC will clear after 50 fault free ignition cycles.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
^ When the warmer (red) switch is active, the input to the DDM is 2.50-3.09V (127-158 counts).
^ When the cooler (blue) switch is active, the input to the DDM is 0.99-1.58V (51-81 counts).
^ When neither switch is active, the input to the DDM is 3.99-4.58V (204-234 counts).
^ Refer to Testing for Intermittent and Poor Connections.

TEST DESCRIPTION

Steps 1-12:

The numbers below refer to the step numbers on the diagnostic table.
2. The value given is the normal condition that exists when no switch is activated.
3. Tests for the proper operation of the circuit in the high voltage range.
4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.