Floor/Defrost Mode Door Control Circuit Open (MTC)
B1049-FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT OPEN (MTC)B1049 - Floor/Defrost Mode Door Control Circuit Open (MTC):
Theory of Operation
The A/C Heater Control drives the Mode Door 2 (Floor to Defrost) Actuator via the (C801) Mode Door 2 Driver circuit and the (C34) Front Common Door Driver circuit. All of the front door actuators share the (C34) Front Common Door Driver circuit. Inside the A/C Heater Control, each door actuator has its own unique driver, but all share a single common door driver circuit. Due to the shared circuitry similar DTCs can set at the same time for multiple actuators depending upon the location of the open circuit and the direction the actuator is moving when the open is present.
WHEN MONITORED
With the ignition on.
SET CONDITION
If the Mode Door 2 (Floor to Defrost) Actuator's electrical circuit is open. This DTC has a maturing time of 5 seconds and a de-maturing time of 10 seconds. If the DTC's status changes from active to stored it will stay in memory for 100 ignition cycles.
POSSIBLE CAUSES
- (C801) Mode door 2 driver circuit open
- (C34) Front common door driver circuit open
- Mode door 2 (floor to defrost) actuator
- A/C heater control
NOTE: DTC B1049 must be active for the results of this test to be valid. Do not perform this test if DTC B1049 is stored. Refer to HVAC System Test (MTC) for stored DTC test procedures. HVAC System Test (MTC)
Diagnostic Test
1. CHECK FOR ACTIVE CONTROL CIRCUIT/PERFORMANCE DTCs
Turn the ignition on.
With the scan tool, read active HVAC DTCs.
Q: Does the scan tool display any active: XXXX CONTROL CIRCUIT/PERFORMANCE DTCs?
YES: Diagnose and repair the DTC(s).
NO: Go To 2
2. CHECK MODE DOOR 2 (FLOOR TO DEFROST) ACTUATOR CIRCUIT RESISTANCE
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance between the (C801) Mode Door 2 Driver circuit and the (C34) Front Common Door Driver circuit in the A/C Heater Control C1 harness connector.
Q: Is the resistance above 70 ohms?
YES: Go To 3
NO: Replace the A/C Heater Control.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
3. CHECK (C801) MODE DOOR 2 DRIVER CIRCUIT FOR AN OPEN
Disconnect the Mode Door 2 (Floor to Defrost) Actuator harness connector.
Measure the resistance of the (C801) Mode Door 2 Driver circuit between the A/C Heater Control C1 harness connector and the Mode Door 2 (Floor to Defrost) Actuator harness connector.
Q: Is the resistance below 5.0 ohms?
YES: Go To 4
NO: Repair the (C801) Mode Door 2 Driver circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
4. CHECK (C34) FRONT COMMON DOOR DRIVER CIRCUIT FOR AN OPEN
Measure the resistance of the (C34) Front Common Door Driver circuit between the A/C Heater Control C1 harness connector and the Mode Door 2 (Floor to Defrost) Actuator harness connector.
Q: Is the resistance below 5.0 ohms?
YES: Replace the Mode Door 2 (Floor to Defrost) Actuator.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (C34) Front Common Door Driver circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test