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Q: alternator problems on 1990 Ford Mustang GT

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
how do i tell if the alternator is working
No car image 94a1663db56199c5353592009e34aaa51078a2469bed068bb8d6f0ba43accf97
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put a voltmeter on the battery with the motor running. it should be between 13.7 and 14.5 volts. any lower and you may have a failure.

Roy
On most cars all you have to do is unhook the positive side of the battery when the car is running. If it dies the alternator is not working. If it is not working your battery will just run out of juice, no light, no start.
Check the voltage at the battery, you can do it with the lights on to see if it holds under load.
DO NOT REMOVE THE CABLES WHILE THE ENGINE IS RUNNING!
This worked on older cars but ones with computers are sensitive to voltage spikes wich you will get if you remove a cable while its running.

Steve
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