My fellow 'Stangers I need some help! I've been dealing with this problem with my '65 Fastback, 289 for a few months now and it's gotten the best of me.
This is where I'm sitting: replaced the alternator, battery, alternator wiring harness and voltage regulator. STILL my ALT light is on.
Removed the alternator and it checked out good. Reinstalled it and
verified the negative batt. cables and connections by measuring from the alternator case to the negative battery post. A reading higher than 0.25v indicates a problem with the negative batt. cable or connections to frame/chassis and enging block. I got 0.00v.
I then checked the positive batt. cables and connections by measuring from the alternator output terminal to the positive batt. post. A reading higher than 0.35v indicates a problem with the positive batt. terminal to alternator or fuse block connections. I got 0.00v here as well.
Now I'm not getting any reading...what the heck does that mean? Is that good or bad? I'd be happy with .05v. Give me some kind of reading. I've checked my connections over and over, sober and drunk, clothed and nude. I swear they are connected correctly.
Going from post to post on the batt. it's lower than 13v.
The only thing left to check is the voltage regulator and wires that connect to it. How do you do it and what am I looking for. Is there anything that I am over looking? Could it be a bad ground?
I don't want to take the voltage regulator any where to get it checked out. Yesterday I had to show 2 guys at 2 different stores how to hook the alternator up to the test bench. Manny, Moe and Jack would have died ashamed and Auto Zone wasn't in the zone. NAPA didn't have test leads that went back to 1965.
I'm at my end with this problem and may find it easier to throw some jumper cables in the trunk and call it fixed. Please, help a brother out.