QuestionQUESTION: Is the safety brake light located in the rear window supposed to come on when the lights are turned on or only when the brake is applied? '99 Hyundai Elantra.
ANSWER: The lamp in the rear window should illuminate only when the brakes are applied. It is intended as a brake lamp only, not a tail lamp.
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QUESTION: Since it does light as a tail lamp also what might be the cause of this problem? I have already checked that the switch on the brake pedal is not stuck and the light operates correctly when the lights are not turned on, .e.g. it only comes on when the brake is applied.
AnswerMost likely, the contacts in one of your outer tail/brake lamp sockets are shorted together. This could be due to a short in a bulb, an improperly installed bulb, a piece of slag from the bulb contacts shorting the socket contacts together, or a defective socket.
To start, remove one of the tail brake bulbs. If the high mounted stop lamp goes out, check for the problem in that bulb or socket. If it stays on, reinstall the bulb and repeat with the other side.
