Ok here is what I got. New Regulator, battery, alternator, and starter. i have checked everything I could check from ohms to fusible links and everything is good. Now to my latest check I disconnected the plug from the voltage regulator. I hooked a jumper wire from the A terminal to the F terminal on the plug. Then I connected my meter to the battery and was getting 14 volts while the car was running. With the regulator connected and the engine running the meter was only reading twelve volts. Does anyone know what the means?
jumping the A to the F terminal actually full fields the alternator, forcing maximum charging output. The regulator controls the current to the F terminal thus controlling output. I'm not sure what you've got going on there, but there has to be something missing. With the regulator plug unplugged, you should have 12v on the A circuit, KOER you should have 12v on the I terminal (regulator disconnected), about 1/2 battery voltage on the S terminal so about 6-7v. The F circuit should have very little or no voltage but you may read something with a high impedance meter. When the car starts, voltage is supplied via the I circuit, this energizes the regulator and field, the S circuit gets a reduced voltage from the rectifier inside the alternator and when voltage is sufficient (above approx 6.5v indicating a charging voltage of at least 12.6v) it will unground the circuit for the light and allow the light to go out. You may try connecting a jumper wire from the alternator small ground to the regulator housing at one of the attaching screws just to see if it makes a difference. I had a 1985 EXP with these same issues and I went through 5 reman alternators before I got a good one. Is your wiring stock or has it been modified in any way? Check the voltages I mentioned above and see what you have. Hopefully this will help you narrow it down.
Okay. You have a new voltage regulator, battery, alternator, and starter... ...from what you described above, it sounds like a wiring problem. The most likely culprit...from what you describe...is the way you have your voltage regulator wired. A missing Battery +12v on the "A" terminal, or if the voltage regulator isn't grounded, could cause what you are describing. I agree with InjectedMav's post, except where he says: "When the car starts, voltage is supplied via the I circuit, this energizes the regulator and field,..." I think he meant to say that the "F" terminal on the voltage regulator is what energizes the rotor's field winding, when the car is running. The "I" terminal is what feeds positve voltage to one side of the alternator light, which turns the light off when the charging circuit is working, because the other side of the alt light has the positive voltage coming from the ignition on switch, and they cancel each other out. I posted a new wiring diagram for you, and added more detail, that wasn't shown in the original drawing. 1. Make sure you check ALL your ignition and charging circuit wiring. 2. Don't assume the connectors are good, especially on the voltage regulator. Check with an Ohmmeter.
Sorry for the confusion, I didn't want to get too much into detail, I was afraid I was getting long winded as it was. I just simplified the explanation from I to F terminals for the sake of simplicity. The I circuit is the regulators' "turn on" power from the ignition switch. From this circuit the regulators' electronics are energized and is simply a wake up circuit to tell the regulator to control the field of the alternator. The A circuit is the battery voltage sense circuit and is actually where the field power is supplied. All of the non OEM replacement regulators that I know of are solid state and control the field with power transistors instead of relays and the only differences between them may be that some are configured to operate with an ammeter instead of a light. In that case, the I circuit comes directly from the switch or is omitted entirely.:Handshake
No worries InjectedMav. I appreciate you chiming in also. We are both just trying to help Rome get his electrical problem fixed...the more of us with electrical/electronics experience, the better! I don't mind sounding long-winded on this stuff....these electrical issues can be a pain in the (you know what)....so I like your point about the "A" terminal on the regulator....and since that is a tricky closed loop circuit...I will explain it even further...just for the fun of it! I agree that the "A" terminal on the voltage regulator, is the battery sense lead, (a closed loop feedback circuit) which in turn causes the voltage regulator to increase or decrease the Alternator rotor's Field winding voltage from terminal "F" on the regulator (which is attached to "F" on the alternator), which in turn causes the Alternator's output on the "B" connection to charge the battery....which brings us full circle to the "A" terminal sensing this battery voltage...on this feedback circuit. :Handshake And yes...I agree...the cars with the ammeter instead of the just the alternator light have different wiring. Don't worry, I wont get long winded about that one. unless someone has problem with that issue.
I would also do a pin pull test on that voltage regulator plug. Find a male spade terminal that is the same size as the ones on the regulator, and test each female spade connector in the regulator plug. There should be resistance (not the electrical kind) when you insert and remove the male spade terminal. If it is very easy or sloppy, I would replace that female terminal. you can also cheat and give each male terminal on the regulator a slight twist, but that is not a permanent fix. but it could allow you to eliminate the terminals as a problem.
Thanks for all the info. I will print everything out and start checking. I will get back as soon as I find something. When it comes to electrical work I am an idiot. Thank God for people like you!!
IF it full fields by jumping it I would plug in a known good regulator. Just because its new doesnt mean its GOOD. You figure that out in this trade real fast.
