how can i test my alternator and voltage regulator to see which one is bad?

[BigBlockSam]

hi guys , i have a 1969 daytona clone with a 440 motor and when i put a volt meter across the batt terminals i get the same reading weather the car is running or not . so it's not charging . stock alt and external reg. i've seen people full feild the alt to see if it's any good . how do i do that . thank you 

[Pete in NH]

Hi,

On a stock 69 set up, disconnect the green wire on the field connection on the back of the alternator. Then connect the field terminal on the back of the alternator to either the output stud on the alternator or the positive terminal of the battery. This will "full field" the alternator and if the alternator is good a voltmeter across the battery will show something like 16 -17 volts. Don't run it too long like this as you will damage the battery and other electrical things on the car. If the voltage does come up the alternator is good and the problem is something in the regulator area. If the voltage doesn't come up the alternator is likely the problem.

[BigBlockSam]

very, very cool . Thank you 

[c00nhunterjoe]

Dont do this without a limiter if you have msd or any other ready to run style ecu.