Ford Grand Marquis Owner's Manual page 243

The driving modes required to reach the ready
condition consist of a minimum of 30 minutes of
city and highway driving as described below:
At least twenty minutes driving in stop and
go, city type traffic with at least four idle
periods.
At least ten minutes of driving on an
expressway or highway.
Before completing the above driving modes, the
engine must be warmed up and at operating
temperature. Once started, the vehicle must not
be turned off during these driving modes.
Lights and Bulb Replacement
It is a good idea to check the operation of the
following lights frequently:
headlamps
tail lamps
brakelamps
hazard flasher
high-mount brakelamp
turn signals
side markers
license plate lamps
The alignment of your headlamps should be
checked if:
oncoming motorists frequently signal you to
turn off your vehicle's high beams when you
do not have the high beams on
the headlamps do not seem to give you
enough light to see clearly at night
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