What Does B2561 Mean?
This code indicates the Body Control Module (BCM) has detected a malfunction in the speed 1 circuit of the auxiliary air conditioning blower motor. The BCM monitors the blower motor control circuit and has identified either an open circuit, short circuit, excessive resistance, or failure of the blower motor to respond to commanded speed. This typically affects rear or auxiliary climate control systems in vehicles equipped with dual or tri-zone HVAC systems.
Common Causes
35%
Faulty auxiliary blower motor with internal winding failure or seized bearings
30%
Damaged wiring harness or corroded connectors in the blower motor circuit
20%
Failed blower motor resistor or speed control module
10%
Blown fuse or failed relay in the auxiliary blower circuit
5%
Faulty BCM with internal driver circuit failure
Diagnostic Steps
1
Step 1: Perform visual inspection of auxiliary blower motor and associated wiring harness for obvious damage, burnt connections, or corrosion at the blower motor connector located in rear HVAC housing
2
Step 2: Check auxiliary blower motor fuse and relay in appropriate fuse box, verify fuse continuity with multimeter and test relay operation (should hear click when activated)
3
Step 3: With ignition on, use multimeter to verify battery voltage (12-14V) at blower motor connector power supply wire, then check ground circuit for less than 0.5 ohms resistance to chassis ground
4
Step 4: Disconnect blower motor connector and apply direct 12V power and ground to motor terminals to verify motor operation; if motor runs, problem is in control circuit; if motor fails to run or runs slowly, replace blower motor
5
Step 5: If motor operates with direct power, backprobe the blower motor speed control signal wire at the BCM connector with multimeter set to DC voltage while commanding speed 1 via scan tool to verify BCM is sending proper control signal (typically PWM signal or varying voltage)
6
Step 6: After repairs, clear codes, operate auxiliary blower through all speed settings including speed 1, and verify proper operation with no code return
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a malfunction in the speed 1 circuit of the auxiliary air conditioning blower motor. The BCM monitors the blower motor control circuit and has identified either an open circuit, short circuit, excessive resistance, or failure of the blow...
The most common cause of B2561 (Aux A/C Blower Speed 1 Circuit Failure) is: Faulty auxiliary blower motor with internal winding failure or seized bearings
Typical repair costs for B2561 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects auxiliary climate control comfort functions. Repair at convenience, though passenger comfort in rear seating areas will be compromised, particularly in extreme weather conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2561 to identify the root cause.
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Quick Info
Category
Body
System
Auxiliary Climate Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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