voltage concerns related to alternator

make sure there is 12v to the big wire in the back. in the 2 wire connector, one should be hot with the key on and the other will have 7 or 8 volts. if you have these readings, replace the alt. Roy

try to connect the neggative connector from the battery terminal to the car's body then measure the voltage again if you still have the same problem thats when you need to change the Alt. because it should read 13.6 when idle.