What does it mean?
C1249 is a Chassis (ABS, traction control, steering) fault code. It indicates: Brake Light Switch Circuit Failure . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- Brake lights permanently on, not working, or working only sometimes
- ABS or stability warning lamp on
- Cruise control refusing to engage, or not cancelling when the pedal is pressed
- Selector lever will not come out of Park on vehicles with a shift interlock
- Auto hold, hill-hold and stop-start functions disabled
- Brake pedal feel normal, so the fault is purely electrical
Likely causes
- Brake pedal switch out of adjustment, or its plunger no longer travelling correctly
- Broken or missing pedal striker pad, leaving the switch permanently in one state
- Failed switch with worn or welded internal contacts
- Open, chafed or shorted wire between the switch and the module
- Corroded or overheated switch connector terminals
- Blown stop lamp fuse or an open supply to the switch
- Trailer socket, alarm or remote start wiring feeding voltage back into the brake circuit
How to fix it
- Check brake lamp operation and the stop lamp fuse first
- Watch the brake switch status on live data while the pedal is pressed and released
- Check switch adjustment and inspect the pedal striker pad, which often crumbles with age
- Measure both switch circuits, since most switches have a normally open and a normally closed contact that must change together
- Inspect the connector for melted, corroded or spread terminals
- Disconnect any trailer, alarm or remote start wiring on the brake circuit and retest
- Adjust or replace the switch, then carry out any switch learn procedure the vehicle requires and verify the lamps and cruise control work