Manual or automatic?
There are a few switches to check. One if the clutch switch (if equipped) and the other is the brake switch. Make sure these are operable. Are you using LED taillights?
Clutch switch is here. Should be closed continuity with the clutch pedal out and open when you push it in
Do you have any issues with your horn or airbag? Does the horn work and is the airbag system functional? The clockspring could potentially have issues.