service now light

hello folks,
i was drving home in my 1985 cadilllac eldorado 4.1 liter and my radio started to destort then die out then my servive now ,light came on .i turned the car off and it repeated itself 3 times i took it to pep boys i was told code #16 came up saying it was a bad alternator i took it out and had check at 3 different auto stores ,all said that the alternator was fine . does anybody out there have any idea on how i can fix my problem?
thank you for you time and good luck to all, cadillac dave

Check the wiring for the alternator and the battery cables. I know that some Cadillacs use the starter motor wiring for a battery sense wire. It tells the alternator what the system voltage is, and when to charge or not. I had a bad battery sense wire going to the starter on my '94 Deville, and I had charging problems.

thank you caddydaddy
i'll give it a try.

Thank you for your help it was the voltage regulater in the alternator it reads fine if you take it out and have it checked so i had it checked with the alternator in the car which i should have done in the first place i was trying to save some bucks. Happy Chinese New Year to ALL. Cadillac Dave.