One problem related to adaptive cruise control has been reported for the 2005 Mercury Grand Marquis. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2005 Mercury Grand Marquis based on all problems reported for the 2005 Grand Marquis.
Neither the air conditioner nor the cruise has worked since 46,000 miles. It needs a new air compressor which would cost over $1,000 and there are several other complaints for this issue plastered all over the internet.