Failed rear blower motor (worn brushes, seized bearing, internal short); Damaged or corroded wiring harness or connector at the blower motor; Blown rear blower motor fuse or faulty relay; Failed blower motor resistor or control module; Poor ground connection for the blower motor circuit; Faulty HVAC control head or body control module (less common)

DTC codes / B03xx · Airbags, seats, doors, lights and comfort systems / B0330

B0330HVAC Rear Blower Motor Circuit

Q: What does code B0330 mean?

HVAC Rear Blower Motor Circuit. B0330 indicates that the body control module (BCM) or HVAC control module has detected an abnormal condition in the rear blower motor circuit, such as an open, short to ground, short to power, or excessive current draw. The module monitors the circuit and sets this code when the feedback voltage or current does not match the commanded output for the rear blower speed.

B0330 indicates that the body control module (BCM) or HVAC control module has detected an abnormal condition in the rear blower motor circuit, such as an open, short to ground, short to power, or excessive current draw. The module monitors the circuit and sets this code when the feedback voltage or current does not match the commanded output for the rear blower speed.

SystemBody

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

Rear blower motor does not run at any speed setting
Rear blower motor runs only on certain speeds or not at all
Blower motor stays on continuously regardless of setting
Blower motor fuse blows repeatedly
Often no symptoms besides the warning light if the fault is intermittent
Weak or no airflow from rear vents

Common causes, most likely first

Failed rear blower motor (worn brushes, seized bearing, internal short)
Damaged or corroded wiring harness or connector at the blower motor
Blown rear blower motor fuse or faulty relay
Failed blower motor resistor or control module
Poor ground connection for the blower motor circuit
Faulty HVAC control head or body control module (less common)

How to diagnose and fix it

Check the rear blower motor fuse and replace if blown; if it blows again, inspect for shorts
Inspect the blower motor connector and wiring for corrosion, burns, or loose pins
Measure voltage at the blower motor connector with the rear blower commanded on; compare to battery voltage
Test the blower motor by applying battery voltage directly; replace if it does not run smoothly
Check the blower motor resistor or control module for continuity and correct resistance values
Verify the ground circuit from the blower motor to chassis with a voltage drop test
If all components test good, diagnose the HVAC control head or BCM signals with a scan tool

Before you replace the rear blower motor

A corroded connector at the blower motor resistor is a frequent cause that mimics a failed motor, so always inspect the pins before condemning parts.
The rear blower circuit often shares a ground with other body components; a bad ground can set B0330 along with unrelated codes.
Intermittent B0330 may be caused by a chafed wire in the rear quarter panel or liftgate area where the harness flexes.
Some vehicles use a pulse-width modulated (PWM) signal to control blower speed; a failed solid-state driver in the control module can set this code without any wiring fault.
Do not overlook a weak battery or charging system issue, as low voltage can cause the module to misreport a circuit fault.

Can I keep driving with B0330?

The vehicle remains safe to drive because the rear blower motor only affects passenger comfort, but avoid using the rear HVAC system until the fault is repaired to prevent further damage or a blown fuse.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.