New to forums, new to Mustangs

Hello all! Got my license in '65, wanted a new mustang REAL bad! Now, 4 years later, I finally got one, could not be more proud. It's restored well,, but alternator light has started flashing any time motor is running but alt charges battery just fine. If I press brake pedal or turn on lights or fan blower motor, flashing stops. Any clues where to start looking? Any suggestions are greatly appreciated!
THANKS, Lake Martin John, central Alabama. (Roll Tide)!
 

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Hi and welcome, does the light go out with a little increase in RPM? There are a couple of possible causes. The old mechanical regulators are not the best, you can get a direct replacement solid state regulator that's much better at the job, and if you want the old look, change the thin cover for the old thick cover. You could have lost one or two of the diodes in the alternator, it will still work kind of but can cause your symptom, a load test will show that problem. if you mustang is early with a generator, it could be normal, but again the light should go out at higher RPM's. Clean solid electrical connections are a must, check this first. Good luck.
 
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Could be your alternator is getting weak or you have poor connections or really old battery cables. They deteriorate over time and get corrosion build up which doesnt allow them to carry enough current. Most parts stores will test your alternator for free. Then you should check and clean your vable connections and check your alternator connections on the back of the alternator.
 
Could be your alternator is getting weak or you have poor connections or really old battery cables. They deteriorate over time and get corrosion build up which doesnt allow them to carry enough current. Most parts stores will test your alternator for free. Then you should check and clean your vable connections and check your alternator connections on the back of the alternator.

Much thanks TOS, I suspect you are on to something (as was the first responder to my post) that alt might be weak. All connections look clean, volt regulator looks new. I've only owned car a week and have found that the Previous owner recently added air conditioning. Not sure old alternator was upgraded, might not provide enough amps. Will have it tested, may need a bigger one or new brushes etc. in existing one. Again, I SO appreciate stangnet! A great group of people with a wealth of information that they enjoy sharing. So cool!
 
Check your battery voltage when the alternator light is flashing. It should be in the mid to upper 13v range when the engine is idling. If that checks out, then I agree that it's probably something going on with the indicator light circuit rather than the charging circuit.

I didn't get my license in the '65 Mustang I once had, but it was my first car. And it was white.
 
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