i thought my alternator was bad, started with putting out 13.5 volts then when i switched the headlights and ac on it quickly dropped down to 11.5 volts. so i had a 100 amp alternator with a new regulator, switched them out and same thing, so then i started wiggling wires and got it to go up to 13.75, cleaned the part that plugs into the regulator and the two prong plug that comes off the alternator, that seems to of fixed it but still only 13.50 - 13.75 volts. isnt there a way to get 14.5 volts.

 

Try a fulll-field test as outlined in the manual. That basically bypasses the regulator and tells the alternator to produce full power, which tests it.

 

my manual doesnt tell how to do that. ill look online to see if i can find a site that tells.

 

seems that i jump the A & F terminal on the regulator. problem is which are the A & F.

 

 

thanks, thats perfect. now the site i found said to jump the A & F, is that true. if so im guessing that i jump them then start the engine, or start the engine first, then see if im putting out 14 volts or above, or would i still only get the 13.75. in other words what should i expect to on my readings, and how long can i run it like that, i guess just long enough to see what the readings are.

 

Just long enough to see what the reading is. What model are you working on? Has there been any wiring changes done to the vehicle?

Reason I ask is I use a Fox Mustang harness in my Falcon and it was doing pretty much the same thing. Turned out the alternator harness had been redone by the owner of the donor car. The wire for the regulator voltage sense had been reconnected in the wrong place. I fixed that and now it charges close to 15v.

 

the wiring hasnt been mess with ans is all stock, 70 mustang. i found that if i wiggled the big wire that goes to the battery side of the starter relay the voltage dropped then went back up. so i kept wiggling it until i pinned it down to where it connects in the loom. it connects from one wire into two wires and has a good size rubber insulator around it. i cut it there and soldered a new wire from the two wires and soldered a new connector at the other end. now my voltage reads constant. this all started when my wife said her dash lights dimmed when she turned the ac on, i thought she was saying they were staying dim, she says not really but they were brighter a few weeks ago. i drove it now and it will charge about 14 volts with the headlights and ac on but the dash light do look dim. any ideas on how to check to see that there getting the full voltage to them, by the way my charge does show charge.

 

well come to find out the wire that connects to the battery side of the starter solenoid was bad and had a bad ground on the wire that comes through the fire wall, fixed them and im charging and dash lights are bright again, thanks for any help from fellow mustangers.