IS IT THE BATTERY OR THE ALTERNATOR

SOURCE: My Ford Expedition cuts off after running. Need

Taking off the negative battery cable will tell you if a alternator is bad most of the time but not all the time. If you can remove the alternator and take it to a automotive shop and get it tested you will get a true reading if it's bad usually they will do this for free. Hope this helps.

Ronny Bennett Sr.

• 6988 Answers
• Posted on May 23, 2010

SOURCE: 2002 ford ranger quit running on highway, pulled

If the starter is just clicking,then it is not,but if the starter is kicking the starter drive out,and that is the noise you are hearing then it might be,turn the crank pulley with a socket and ratchet ,clock wise,if it turns then this is not the problem,make sure the ground to the engine is good,if the ground cable has gone bad,this will happen.

ZJ Limited

• 17989 Answers
• Posted on Jul 05, 2010

SOURCE: 1999 ford mustang cobra alternator troubleshooting

Generally, you can check and test alternator with this procedure...

1. Clean the positive and negative battery terminals to ensure a good connection with the tester's clamps.
2. Connect the positive and negative clamps to the appropriate battery terminals. The clamps must make firm contact with the battery terminals or the test results will be inaccurate or the tester may not work at all.
3. Turn the tester on and choose the option for "full charging system test." This will test your battery, starter and alternator and provide the most accurate picture of the problem.
4. Follow the directions on the tester's screen. These instructions will include cranking the vehicle after the battery test is performed, holding the engine at a certain RPM range and turning on certain accessories.
5. Read the results displayed on the tester's screen. The tester should scroll through the results, starting with the battery, then the starter and finally the alternator. An alternator test result showing diode ripple problems indicates a bad alternator.

Hope helps (remember rated this).

SOURCE: 2004 ford focus se replaced alternator

Sounds to me that your battery has shorted out and will not take a charge.Disconnect the battery and try to charge it, then check to see if it has taken power with a volt meter. A shorted battery will take all the power from the alternator and run it to ground leaving no power to run the car. Also check the alternator output with a volt meter after you have checked the battery as a shorted battery can burn out the alternator.

SOURCE: I have a 94 Mustang

Check your crank and cam position sensors as they are prone to heat induced failure. The cam sensor is usually magnetic and the cam sensor Hall effect. I am 95% sure that your fault lies with either one of there sensors. 2 pin socket (magnetic - sine wave output). One pin is 'ground' the other is 'signal'. A voltmeter set to 2 volts AC should measure a signal in the 0.2 to 2 volts range on the 'signal' pin.

3 pin socket (Hall effect, magneto - square wave form output). One pin is 'reference' (5volts), one pin is 'ground' and the third pin is 'signal'. A DC voltage should be detectable in the 0.5 to 1.5 volt range from the 'signal' pin.
It is important that the voltage measurement take place at start up when the engine is cold and again, 20 minutes later, when the engine has fully warmed up to operating temperature. Often the voltage output from faulty sensors declines with temperature rise. Just replace the faulty sensor.