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I've looked at a bunch of these so its good to see I'm not alone. I have changed everything in mycharging system and still is not charging. I'm looking for a diagram for the 1979 351m bronco with alt light alternator. mine has three connectors the batt and two other one has dual wires. anyone please help newbie needs it.
According to the diagram I have in my Hayne's manual for 1979 Bronco's -
The three outputs from the alternator are labelled as F, S, and B.
An orange wire goes from F on the alternator to F on the alternator regulator.
A white/black wire goes from S on the alternator to S on the alternator regulator.
A black/red wire is connected to B on the alternator to a yellow wire which goes to A+ on the alternator regulator as well as being connected to the hot terminal of the starter relay.
Just a quick question do you have power going to the alternator? Is there power at the B terminal on the alt. You must have power there you can use a test light to see. I you don't have power there you could have a bad fusable link.
According to the schematic I have, there is no fusible link between the Batt and B. The only fusible link that Haynes shows is between the ignition switch and starter relay / horn. Therefore, 'B' should always have power regardless of the ignition switch position.
I don't have a 79 Haynes book mine is 80 & up and they show fuseable links. Yes there should be power there at all times. There must be some type of pertection for that circuit Where does your book say the power comes from? most of the time that curcuit starts at the battery side of the starter relay. the fuseable link should be right there.
Yeah, Haynes says the power comes right off the hot side of the batt to the starter relay and then to the alternator - no protection shown on that line. My 79 is parked in storage so I can't take a boo to see whether or not there is a fusible link. It would make sense to me too, for there to be a fuse between the two.
Go figure checked and the new alternator from Auto **** was no good. I even bought the lifetime one to avoid this problem. Thanks for all the help would have never figured it out otherwise.