I took my 1996 C36 for an oil and spark plug change. When I got the car home the red light on the central locking switch was on. The light will not go out. This light is supposed to blink when the alarm is armed. I have tried using the trunk lock, remote on key and disconnecting the battery. The light stays on at all times and the switch will lock and unlock the doors. Any suggestions would be greatly appreciated. Thanks in advance for any suggestions.