See also:

Trailer brakes
If your trailer is equipped with a braking system, make sure it conforms to federal and/or local regulations and that it is properly installed. Never connect a trailer brake system directly ...

Turn signal/hazard indicator lights
The appropriate light flashes when the turn signal switch is activated. Both lights flash when the hazard switch is turned on. ...

Engine block heater (if so equipped)
● Do not use your engine block heater with an ungrounded electrical system or a 2-pronged adapter. You can be seriously injured by an electrical shock if you use an ungrounded connec ...