Defect
On certain vehicles, the engine block heater could leak coolant. If this happens, the block heater could short circuit when it's plugged in.
Safety Risk
A short circuit can create the risk of a fire.
Remedy
To reduce the safety risk, Ford advises you not to use the engine block heater until the recall repairs have been completed. Ford will notify owners by mail and advise you to take your vehicle to a dealership to replace the block heater.