Originally Posted by SixFo Galaxie
Do any of you have step by step instruction's how to check it out with a multi meter? The batterys voltage is at around 12.30 with the car off and at idle. Shouldn't the voltage go up with then car is running? The little Gen light is also on while the car is driven and at idle. Thanks
Get a multimeter and set it to DC Voltage, if it has a range set it to 20 volts. start the car and while it is idling you should get at the minimum 13 volts but an alternator in good condition should charge at between 13.8 and 14.2.
One more thing you might want to check is for current draw when the car is off. There are diodes in the alternator which stop the alternator draining the battery when the car is switched off. These sometimes stuff up and create a current draw when the engine is stopped draining your battery. A quick way to check this is get a flat screwdriver while the car is running and just put the blade in front of the pulley (Watch the belts and radiator fan). If the screwdriver magnetises to the pulley get an auto leccy to check it out.
Another way to check if anything is drawing current.
Turn the car off, close doors lights off, key off etc. Get your multimeter set it to amps and switch the positive lead over to amps (It will have 10A above it.) which means it is fused. Take a battery terminal off (preferably postive) and put the meter between the postive terminal and the lead you just removed. If you get anything above .4 you its a worry. Take your car to an auto leccy if the current draw is too high.
Hope this helps.