One problem related to ignition module has been reported for the 2008 Mercury Mariner. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Mercury Mariner based on all problems reported for the 2008 Mariner.
Manufacturer's faulty ignition lock module wears out prematurely and vehicle often doesn't start. Caused consistent but intermittent problem for last 3 years. Research shows this is a common problem on 2008-2012 Mariners, Ford escapes and 2008-2011 Ford focus, which all use the same ignition lock.