HVAC - Automatic
DTC B0193
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B0193 01
- Front Blower Motor Speed Circuit Short to Battery
DTC B0193 06
- Front Blower Motor Speed Circuit Low Voltage/Open
Diagnostic Fault Information
Circuit/System Description
The blower motor control module is an interface between the HVAC control module and the blower motor. The blower motor speed control from the HVAC control module, battery positive and ground circuits enable the blower motor control module to operate. The HVAC control module provides a pulse width modulation (PWM) signal to the blower motor control module in order to command the blower motor speed. The blower motor control module transfers the PWM signal into a corresponding blower motor voltage. The voltage resides between 2-13 V and changes linear to the height of the PWM signal.
Conditions for Running the DTC
* Ignition ON.
* The HVAC control module is ON.
Conditions for Setting the DTC
B0193 01
The voltage at the HVAC control module output to the blower motor control module is always high.
B0193 06
The voltage at the HVAC control module output to the blower motor control module is always low or floating.
Action Taken When the DTC Sets
The blower motor is inoperative.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
HVAC Schematics (HVAC - Automatic)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Automatic HVAC Description and Operation (HVAC - Automatic)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the K8 Blower Motor Control Module.
2. Test for less than 5 ohm between the ground circuit terminal 5 X1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 6 X1 at the K8 Blower Motor Control Module harness connector and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.
5. Ignition ON, test for less than 0.3 V between the control circuit terminal 3 X1 at the K8 Blower Motor Control Module harness connector and ground.
• If greater than the specified range, test the control circuit for a short to voltage.
6. Ignition OFF, test for infinite resistance between the control circuit terminal 3 X1 at the K8 Blower Motor Control Module harness connector and ground.
• If less than the specified range, test the control circuit for a short to ground.
7. Test for less than 5 ohm between the K33 HVAC Control Module control circuit terminal 15 X2 and control circuit terminal 3 X1 at the K8 Blower Motor Control Module harness connector.
• If greater than the specified value, test the control circuit for an open/high resistance.
8. If all circuits test normal, replace the K8 Blower Motor Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Blower Motor Control Module Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for HVAC control module replacement, setup, and programming