B1350 code definition

The B1350 trouble code detects an error with the heated backlight relay.

What the B1350 code means

The B1350 code is a generic OBD-II trouble code that signals a malfunction with the heated backlight relay, with the backlight referring to the vehicle’s rear windshield. The heated backlight system is responsible for heating the rear windshield to aid visibility for the driver. When the vehicle detects that the heated backlight system is not operating properly, then the B1350 trouble code will be stored.

What causes the B1350 code?

Common causes for the B1350 trouble code include:

What are the symptoms of the B1350 code?

A vehicle with the B1350 trouble code likely will not be able to heat the rear windshield. This can cause visibility concerns, especially during cold weather.

How does a mechanic diagnose the B1350 code?

The B1350 code will be diagnosed using a standard OBD-II trouble code scanner. A certified technician will view the freeze frame data to assess the code, and check for any additional trouble codes that are present. If numerous codes are detected, then the mechanic will need to address them in the order in which the scanner displays them. The trouble codes will then be reset, the vehicle will be restarted, and the mechanic will check to see if the B1350 code remains detected. If not, then it was probably erroneously detected, or is the result of an intermittent error.

If the code remains detected, then the mechanic will perform a visual inspection of the heated backlight system. Any wires, connectors, or fuses that are damaged will need to be replaced. The mechanic should thoroughly inspect the fuses, as they are the most likely culprit of the B1350 code. The technician will then test the heated backlight relay to see if it is functioning and receiving power. If the issue is not yet found, then a defective heated backlight switch should be assumed.

Any time a component is replaced, the mechanic should reset the trouble codes, restart the vehicle, and look to see if the B1350 code is still detected. This will allow the technician to know as soon as the issue is resolved.

Common mistakes when diagnosing the B1350 code

The most frequently made mistake when diagnosing this code is the failure to properly follow the OBD-II trouble code diagnosis protocol. The protocol should be followed during all diagnoses, as it helps make sure that inspections are efficient, thorough, and devoid of unnecessary replacements.

Fully functional heated backlight relays are frequently replaced because a blown fuse was overlooked.

How serious is the B1350 code?

A vehicle with the B1350 trouble code won’t experience any drivability issues. However, the heated backlight serves as a safety feature that aids driver visibility, so the vehicle should be inspected when the code is detected.

What repairs can fix the B1350 code?

Repairs for the B1350 trouble code are:

  • Heated backlight relay replacement
  • Heated backlight switch replacement
  • Replacement of wires, connectors, and fuses

Additional comments for consideration regarding the B1350 code

The B1350 trouble code only applies to vehicles that have a heated rear windshield feature. For vehicles that do, the heated backlight switch is usually the same switch as the heated mirror switch.

Need help with a B1350 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

This article originally appeared on YourMechanic.com as B1350 OBD-II Trouble Code: Heated Backlight Relay Short to Ground and was authored by Brady Klopfer.


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