What you really mean is a sure way to blow the alternater and all of the sensitive electrical components! I know of NO procedure that advocates disconnecting the alternater while the motor is running! Put a voltmeter on the battery, read the voltage, start the motor and read again after about 1 minute. It should read at least .5 volts higher. A better test is to use an alternater tester which measures ripple so as to determine if any diodes are shot and full load output. Disconnecting the alternater while the motor is running will send a surge of over 100 volts through the system. If it doesn't cause outright damage immediatly you will see things happen later like bulbs blowing and computers dying. (Take note if automatic!) * HINT* A quick and dirty way to see if the alternater is charging is to take something magnetic (like a pocket knife) and hold it close the the bearing on the end of the rotor away from the pulley. You will feel a strong magnetic attraction if the alternater is charging the battery. This is not a quantitative test, just a go-no go way to see if the alternater is working at all. You could also use a test light. It should be a little brighter when the motor is running then when it is off. There is no substitute for good test equipment and the knowledge to use it. David Teitelbaum vin 10757 --- In dmcnews@xxxx, "sk1pper" <sk1pper@xxxx> wrote: > A sure way of testing the alternator is to start the car then remove one of the battery leads (preferbally the positive), then test the pos and neg for 12-17vDC. This will tell you if the alternator is producing electricity. I had to change my alternator and all was ok partly due to the old motorolla only producing 68vDC and the old rusted nuts causing resistance shorting out the charge. If you need to change the alternator, I have a list of part numbers that will get you a straight replacement from your local parts store, OR if you are like me, more power is always the way to go. I will have a new web page up in about 2-3 days @ www.sk1pper.com that has pic of mine and how i put a 140a alternator on. > > Let me know if you need any more info or if this even helps ... > > > sk1pper landry > > > >