Jeep 2008 Wrangler Owner's Manual page 200

The defroster will automatically turn off after about ten
minutes. For five more minutes of operation, press the
switch again. To prevent excessive battery drain, use the
defroster only when the engine is operating.
UNDERSTANDING THE FEATURES OF YOUR VEHICLE 199
CAUTION!
Use care when washing the inside of the rear window
to prevent damage to heating elements. Use a soft
cloth and a mild washing solution, wiping parallel to
the heating elements. Also, keep all objects a safe
distance from the window to prevent damaging the
heating elements.
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