switching alternators.
 

here's the deal. i have a 73 super and the alternator went out. i purchased a new alternator that had an internal regulator, but the stock set up is with an external regulator. i got everything set up the way i was told and fired up the car. ran great. better than before. a day later a go to start up my car and the alternator light is on along with the brake light. they both stay on the entire time i drive. this isn't right. can anyone tell me how to properly wire up the new alternator with internal reg. instead of external. i must be wiring something wrong. if anyone one has had experience with changing alternators, please help me. other than that the car runs superb. thanks a lot.

re: Switching Alternators
 

There are a few concerns when an electrical system is not functioning properly. First, be sure to check all cable connections and make sure the alternator is grounded. We suggest grounding to the negative terminal of the battery to ensure the best ground possible. Second, be sure to check the resting voltage of the battery. 12.8 volts is standard. If your batter is low, charge it fully. This single issue can lead to the death of your alternator. Third, turn the car on and check both the voltage of the battery (should be upwards of 14v+) as well as the voltage of the output stud of the alternator. Lastly, rev the engine to 2000 RPM and see if the voltage dips while running some accessories (AC, lights, stereo.) Usually, the first few steps will isolate and help you eliminate the problem. We have a lot of instructional and informational videos on our youtube page under MechmanAlternators. Please be sure to check us out!

Thank you and good luck!

You have dragged up an old thread. Who's instructions did you follow?

It depends on which alternator your fitting. Generally the small wire is the exciter which come from the generator warning light. The power cables charge the battery and other electricals.