Aux A/C Blower Speed 2 Circuit Short to Ground
The auxiliary A/C blower motor speed circuit 2 has shorted to ground, meaning the electrical signal is grounded instead of operating normally. It's like a light switch that's stuck in the ON position due to a wire touching metal.
The ECU monitors the voltage signal on the auxiliary blower speed 2 control circuit. It expects a modulated voltage signal between 0-12V depending on commanded speed. A short to ground pulls the voltage to 0V continuously, triggering the fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Speed 2 Circuit Voltage | 0-12V modulated based on demand | Stuck at 0V or continuous short resistance <5 ohms |
| Circuit Current Draw | 0-15 amps variable | Excessive current >20 amps or no response to PWM signal |
Code B2564 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B2564 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.