1997 Mercury Grand Marquis Owner Guide 1st Printing - Page 155

To turn the heater on, simply plug it into a grounded 110-volt outlet. Ford recommends that you use a 110-volt circuit that is protected by a ground fault circuit interrupter. RWARNING To prevent electrical shock, do not use your heater with ungrounded electrical systems or two-pronged (cheater) adapters. For best results, plug the heater in at least three hours before you start your vehicle. Using the heater for longer than three hours will not damage the engine, so you can plug it in at night to start your vehicle the following morning. NOTE: Be sure to disconnect the engine block heater before driving your vehicle. Guarding Against Exhaust Fumes Carbon monoxide, although colorless and odorless, is present in exhaust fumes. Take precautions to avoid its dangerous effects. RWARNING Do not start your vehicle in a closed garage or in other enclosed areas. Exhaust fumes can be toxic. Always open the garage door before you start the engine. RWARNING If you smell exhaust fumes inside your vehicle, have your dealer inspect your vehicle immediately. Do not drive if you smell exhaust fumes. 155