Check engine, service 4x4, emission system and ABS lights all come on Tachometer and speedometer drop then peg and drop again while driving. It has 102,000 miles just put in a new battery and a new alternator. This just started and it only happens every now and then. It seems to drive and run fine.
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2007 Mercury Mariner
Question: check engine, service 4x4, emission system and ABS lights all come on while driving
Answer #1patrick mannion from Greg Solow's Engine Room, August 19, 2010, 21:22Master
It sounds like an ignition switch problem or alternator problem but the only way to figure out what is going on is to have a wiring diagram and voltmeter and look at the circuits when the "lights are on". If the ignition switch fails to send current out from the switch the car won't charge and bring on the lights, to hard to guess at electrical problems without being able to do some basic tests. With the engine running get a friend to watch the lights on the dash as you wiggle wiring harnesses around the engine compartment to see if you have a bad connection somewhere.