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.
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 Outside Rearview Mirror - Driver
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 Control Module References for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the X2 harness connector at the K8 blower motor control module. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 5 ohms between the ground circuit terminal 5 and ground.
• If 5 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 5 ohms
3. Ignition ON, verify a test lamp illuminates between B+ circuit terminal 6 and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit terminal 6 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K8 blower motor control module.
• If the test lamp illuminates
4. Connect a DMM between the control circuit X2 terminal 3 and ground.
5. Verify the resistance value is between 10 K ohms and 180 K ohms and there is a noticeable change when moving between the commanded fan speeds.
• If not within the specified range or there is no noticeable change
1. Ignition OFF, disconnect the harness connector at the K33 HVAC control module.
2. Test for less than 1 V between the control circuit terminal 3 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
4. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC control module.
• If within the specified range and there is a noticeable change
6. Disconnect the X1 harness connector at the K8 blower motor control module.
7. Connect a 30 A fused jumper between the B+ circuit terminal 1 and B+, and a jumper between the ground circuit terminal 2 and ground.
8. Verify the blower motor operates.
• If the blower motor does not operate
Replace the M8 blower motor.
• If the blower motor operates
9. Replace the K8 blower motor control module
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* HVAC Component Replacement Reference Removal and Replacement
* Control Module References Control Module References for HVAC control module replacement, programming, and setup