Removing a battery cable used to work on the generator type charging systems but is a big NO NO for modern alternator type charging systems especially the new new computerized creatures. The better way to check alternator output is at the 10/32 stud on the back of the alternator using a volt meter. If you have none you can use a pocket knife or a screwdriver to touch the smooth bearing surface on the back of the alternator when the engine is running. If the alternator is working that smooth surface will be magnetized. The more the electrical load ie...headlights on etc etc the stronger the magnetism will be if the alternator is working. No magnetism...alternator not working.....thanks Randy
