Is your brake light on all the time or intermittently? (lower left corner of instrument cluster). This can be repaired - in 99% of cases the problem lies in the instrument cluster. This can be repaired. Visit Instrument Cluster Repair, Speedometer Repair, Odometer Repair for more info.

 

My brake light on dash comes on occasionally. 2006 f150 XLT 5.4 v8 4x4

 

if the brake light comes on during hard turns, hard braking or acceleration, the master cylinder is probably low. if it is low enough to turn the light on, the brake pads need to be looked at.