Ford Repair: alternator, ford fairmont, bench test

Question
QUESTION: I have a 1980 ford fairmont. I m having trouble  with  a  dull glowing alternator light when i slow  down  or  apply the brakes. I just put  a new battery  and  alternaotr in it. And  am still having the same problems when i apply  the gas  the light goes  out. Also  the bel;ts were  check  could it  be anything  with  the  spark plugs? idle?
ANSWER: Ryan, I would start by checking the the alternator.  Take a multi-meter and hold it across the top of the battery while the vehicle is running and see what the voltage is.  It should be above 13 volts.  If it is not, then you can replace the alternator and battery cables, or you can take the alternator to a parts store and have it checked on a bench test.  If it checks out fine, then it is your battery cables, and/or wiring harness, and/or voltage regulator.  If you are getting 13 volts or better to the alternator, then I would take the battery to a parts store and have it checked.  If it checks out fine, then I would check and make sure the belts are not slipping.  Try all this, and if you still are having problems, then write me back.  Good luck,  Jason

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QUESTION: hi, i took it into the shop and they said  the alternator  that i bought yesterday was  bad. I got a new replacment one today and the mechanic hooked it up. He said  it was working good. BUT when i picked it uo  the same thing was happening  i will take it elsewhere but what else could it be??? i put a new battery in 2 days ago. Is there some kind of a regulator that would do this. I aoppreciate your help....... Thanks

Answer
Ryan, you could stop by a parts store and pick up a voltage regulator.  It will be mounted on the front of the car, around the radiator.  That would cause the alternator to test good on a bench test, but act bad on the car.  Also, if you have the original battery cables on the car, now is the time to change them.  Even if that is not the problem, you will get more voltage to the battery.  Honestly, there really isn't much left to replace other than the voltage regulator and the cables.  If the wiring harness to the alternator is old, you might try splicing a new one onto it.  But I would only try that after replacing the voltage regulator and cables.  Try the regulator, then the cables.  If that doesn't work, then let me know.    Jason