Conditions for Setting the DTC
WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.
DTC B257B 03
- The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch B+ circuit.
- The BCM detects a short to ground or an open/high resistance in the instrument panel dimmer switch signal circuit.
DTC B257B 07
The BCM detects a short to voltage in the instrument panel dimmer switch signal circuit.