Failed seat heater element (open circuit in the cushion or backrest pad); Damaged wiring or connector under the seat, often from flexing or pinching; Blown fuse or faulty relay in the seat heater power circuit; Faulty seat heater control module or switch assembly; Corroded or loose ground connection for the seat heater circuit; BCM internal fault (rare but possible)

DTC codes / B03xx · Airbags, seats, doors, lights and comfort systems / B0335

B0335Driver Seat Heater Circuit

Q: What does code B0335 mean?

Driver Seat Heater Circuit. B0335 indicates that the body control module (BCM) has detected an abnormal condition in the driver seat heater circuit, such as an open circuit, short to ground, or short to power. The module monitors the circuit and sets this code when the feedback voltage or current falls outside the expected range during heater operation or self-test.

B0335 indicates that the body control module (BCM) has detected an abnormal condition in the driver seat heater circuit, such as an open circuit, short to ground, or short to power. The module monitors the circuit and sets this code when the feedback voltage or current falls outside the expected range during heater operation or self-test.

SystemBody

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

The driver seat heater fails to warm up at any setting
The seat heater may work intermittently or only on certain settings
The heated seat indicator light may flash or stay off
Often no symptoms besides the warning light, especially if the fault is in a circuit branch not used daily
The seat heater may shut off prematurely after a short period
Other seat functions (power adjustment, memory) may also be affected if they share a common ground or connector

Common causes, most likely first

Failed seat heater element (open circuit in the cushion or backrest pad)
Damaged wiring or connector under the seat, often from flexing or pinching
Blown fuse or faulty relay in the seat heater power circuit
Faulty seat heater control module or switch assembly
Corroded or loose ground connection for the seat heater circuit
BCM internal fault (rare but possible)

How to diagnose and fix it

Check the seat heater fuse and relay, replacing any that are blown or faulty
Inspect the under-seat wiring harness and connectors for damage, corrosion, or loose pins
Measure resistance of the seat heater element with a multimeter and compare to specification
Test the seat heater switch and control module for proper voltage and ground signals
Check the ground circuit for the seat heater, cleaning and tightening connections as needed
If the element is open, replace the seat heater pad or assembly
Clear the code and verify the repair by operating the seat heater through all settings

Common oversights when diagnosing B0335

A seat heater element can fail intermittently when cold, so resistance checks should be done at room temperature and again after the seat has been heated if possible.
The BCM often sets B0335 when the seat heater circuit draws too much current, which can be caused by a shorted element rather than an open one.
Wiring under the seat is frequently damaged by seat movement, so inspect the harness while operating the power seat through its full travel.
Some vehicles use a separate seat heater control module that can fail and set this code even when the element and wiring are good.
B0335 can be stored as a history code after a temporary fault, so always check for pending codes and verify the circuit under load before replacing parts.

Can I keep driving with B0335?

The vehicle remains safe to drive because the seat heater is a comfort feature and does not affect engine or safety systems. Avoid using the seat heater until the fault is repaired to prevent further damage or a possible electrical short.

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.