What Does B2563 Mean?
This code indicates the Body Control Module (BCM) or climate control module has detected a malfunction in the auxiliary air conditioning blower motor speed 2 circuit. The system monitors current flow and feedback signals to ensure the blower operates at the commanded speed, and has identified that speed setting 2 is not functioning as expected. This typically affects rear or auxiliary climate control systems in vehicles equipped with multi-zone HVAC.
Common Causes
35%
Failed auxiliary blower motor resistor or power module causing inability to control speed 2
30%
Damaged or corroded wiring harness between control module and auxiliary blower motor
20%
Faulty auxiliary blower motor with internal fault affecting specific speed operation
10%
Blown fuse or failed relay dedicated to auxiliary blower speed 2 circuit
5%
Failed climate control module or BCM with internal driver circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of auxiliary blower motor and resistor/power module location for signs of water intrusion, corrosion, burnt components, or damaged wiring. Check all related fuses and relays in fuse panel for continuity.
2
Step 2: Using a digital multimeter, verify voltage supply at the blower motor connector when speed 2 is commanded. Expected voltage typically ranges from 6-9 volts depending on system design. Compare to voltage at other speed settings.
3
Step 3: Disconnect the blower motor resistor/power module connector and inspect for burnt pins, corrosion, or melted terminals. Measure resistance across speed 2 circuit per manufacturer specifications (typically 0.5-5 ohms depending on design).
4
Step 4: Backprobe the blower motor connector and measure current draw while commanding speed 2. Compare to specifications (typically 5-15 amps). Excessive current indicates motor fault, no current indicates open circuit or resistor failure.
5
Step 5: If all power and ground circuits test good, perform a direct power test by applying battery voltage through a variable resistor to the blower motor at speed 2 equivalent voltage to verify motor operation.
6
Step 6: After replacing faulty component, clear codes, cycle through all blower speeds multiple times, and road test with auxiliary climate system operating to verify proper operation and ensure code does not return.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) or climate control module has detected a malfunction in the auxiliary air conditioning blower motor speed 2 circuit. The system monitors current flow and feedback signals to ensure the blower operates at the commanded speed, and has identified that s...
The most common cause of B2563 (Aux A/C Blower Speed 2 Circuit Failure) is: Failed auxiliary blower motor resistor or power module causing inability to control speed 2
Typical repair costs for B2563 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 does not affect primary vehicle operation or safety systems. Repair at convenience, though passenger comfort in rear seating area will be compromised due to limited or non-functional auxiliary climate control at speed 2 setting.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2563 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Body
System
Auxiliary Climate Control / HVAC System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
