Why does the car die when the lights are turned on? on 1996 Mercury Grand Marquis

It doesnt matter if its a fast or slow idle, when the lights are turned on,the car dies, if the brake peddle is depressed the car dies. After it dies the wipers come on.

by in Saint Joseph, MO on February 10, 2012
3 answers 1 comment
ANSWER by on February 10, 2012
Have your alternator tested. Sounds like it is not producing enough power to support your auxilliary systems. Probably need to replace it.
ANSWER by on February 10, 2012
Agree with csubak30 It could be a bad or unsecured battery ground cable between the battery and chassis or chassis and engine. Turn on the ignition switch to the on but not run position do you see an icon on the instrument panel representing a battery, if you do not see this battery icon the alternator is not seeing power to allow it to charge. Start the engine does the battery icon go out. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly.
ANSWER by on February 11, 2012
it;s your ALTERNATOR Yor car is running on the BATTERY . Have CAR RUNNING DISCONNECT THE BATTERY ENGINE WILL STOP REPLACE ALTERNATOR
COMMENT by on February 12, 2012
Thank you for your replies, You guys have confirmed my suspicians. I forgot about the disconnect the battery test, since I posted my question the alternator has started whining and found the belt split along it's center line, all telling me the same thing you guys did. Thank you again