Jeep 2010 Wrangler - Diesel Supplement - Manual (Page 30)

ENGINE BLOCK HEATER — IF EQUIPPED
The engine block heater warms engine, and permits
quicker starts in cold weather. Connect the cord to a
standard 110-115 Volt AC electrical outlet with a
grounded, three wire extension cord. The engine block
heater cord is found under the hood near the brake fluid
reservoir.
WARNING!
Remember to disconnect the cord before driving.
Damage to the 110-115 Volt AC electrical cord could
cause electrocution.
Use the heater when temperatures below 0°F (-18°C) are
expected to last for several days.
30 STARTING AND OPERATING