MTC

B1028-REAR BLOWER CONTROL REQUEST INPUT CIRCUIT LOW (MTC)

For a complete wiring diagram REFER to DIAGRAMS/ELECTRICAL .


- When Monitored:
With the ignition on.

- Set Condition:
If the A/C Heater control detects voltage below a calibrated value for a specified amount of time on the (C11) Rear Blower Feed Sense or the (C800) Rear Blend Sense Supply circuits.







NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Refer to HVAC System Test (ATC) for stored DTC test procedures. Heating-A/C System Diagnostics


Diagnostic Test


1. VERIFY THE DTC IS ACTIVE
Turn the ignition on.
With the scan tool, erase A/C Heater Control DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read A/C Heater Control DTCs.
Does the scan tool display this DTC as active?

Yes


- Go To 2.


No


- Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


2. CHECK FOR ACTIVE DTC WITH REAR BLOWER CONTROL SWITCH 8 WAY HARNESS CONNECTOR DISCONNECTED
Turn the ignition off.
Disconnect the Rear Blower Control Switch 8 way harness connector.
Turn the ignition on.
With the scan tool, erase A/C Heater Control DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read A/C Heater Control DTCs.
Does the scan tool display this DTC as active?

Yes


- Go To 3.


No


- Replace the Rear Blower Control Switch.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


3. CHECK THE (C11) REAR BLOWER FEED SENSE CIRCUIT FOR A SHORT TO GROUND




Turn the ignition off.
Disconnect the A/C Heater Control C2 harness connector.
Measure the resistance between ground and the (C11) Rear Blower Feed Sense circuit in the A/C Heater Control C2 way harness connector.
Is the resistance below 5.0 ohms?

Yes


- Repair the (C11) Rear Blower Feed Sense circuit for a short to ground.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


No


- Go To 4.


4. CHECK (C800) REAR BLEND SENSE SUPPLY CIRCUIT FOR A SHORT TO GROUND




Measure the resistance between ground and the (C800) Rear Blend Sense Supply circuit in the A/C Heater Control C2 harness connector.
Is the resistance below 5.0 ohms?

Yes


- Repair the (C800) Rear Blend Sense Supply circuit for a short to ground.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


No


- Go To 5.


5. CHECK THE (C11) REAR BLOWER FEED SENSE CIRCUIT FOR AN OPEN




Measure the resistance of the (C11) Rear Blower Feed Sense circuit between the A/C Heater Control C2 harness connector and the Rear Blower Control Switch 8 way harness connector.
Is the resistance below 5.0 ohms?

Yes


- Repair the (C11) Rear Blower Feed Sense circuit for an open.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


No


- Go To 6.


6. CHECK (C800) REAR BLEND SENSE SUPPLY CIRCUIT FOR AN OPEN




Measure the resistance of the (C800) Rear Blend Sense Supply circuit between the A/C Heater Control C2 way and the Rear A/C Heater Control Switch 8 way harness connector.
Is the resistance below 5.0 ohms?

Yes


- Repair the (C800) Rear Blend Sense Supply circuit for an open.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


No


- Replace the A/C Heater Control.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.