CHARGING ISSUES
 

I HAVE A 1990 MUSTANG GT IT QUIT CHARGING SO PUT A NEW ALTERNATOR ON IT WHEN I CRUNK IT UP IT STARTED CHARGING THEN IT QUIT AGAIN SO I QUIT MESSIN WITH IT THAT NIGHT THE NEXT DAY I WENT OUT TO CRANK IT WHEN I DID IT WAS CHARGING SO I DROVE IT FOR ABOUT 5MIN AND IT QUIT CHARGING I WAS WONDERING IF NE ONE HAD NE TIPS THANKS

sounds like your loosing the 12 volt signal that turns the charging system on

X2
Check the wiring at the connecters at the alternator with the key off. Then turn the key on.There should be one wire that is hot only with the key on. That should be the wire that turns on the alternator. Start the engine and see if the wire is still hot. If it is the alternator should be charging. If there is no hot wire then you need to find a wiring schematic to find out which wire should be the excitation wire. When you find it you can hot wire it to test the alternator output. Good luck on it.

dont know for sure when but for the longest time ford had external regulators sounds like that could be the issue to me jmo

It appears that it should bee an extenal regulator. Here is a schematic that may help.

http://www.veryuseful.com/mustang/te...nks-ign-ac.gif

THANX FOR THE ADVICE