I replaced my alternator and voltage regulator a few weeks ago and ever since I've had to disconnect the battery if the truck was going to sit for more than an hour or 2. I'm pretty sure I've narrowed the problem down to the alternator, but its about an hours drive and 2 border crossings to bring it back to exchange it. I've found that if I disconnect the black and orange (not sure if its one or the other) push on connectors that it doesn't drain the battery. The problem I have is that I don't know what these wires are for and if its ok to leave the disconnected. I know one is for the ammeter, which doesn't work anyways, but I'm unsure which one and I'm at a loss about the other. I've gone though my Chilton but its vague at best. Will definitely be picking up a Haynes next check.

I appreciate any help.

 

Here are links to the Haynes wiring diagrams:

74-78 Wiring Diagram Pt1 (left page)

74-78 Wiring Diagram Pt2 (right page)

 

Don't bother buying another manual. Haynes bought out Chiltons and they are now the exact same book. In some of the pictures in the Chiltons manuals, they are standing in front of a Haynes banner. Haynes had a bad reputation for being not so good, so when Chiltons was having a hard time, they bought the name. All you get now is a Haynes manual with "Chiltons" printed on the cover.

The other wire goes to the voltage regulator. You want that one to be hooked up. It sounds like something is shorted and keeping your field winding charged.

 

Thanks for the help guys. Hopefully I can get this worked out soon. Is it possible for the voltage regulator to cause the drain? I'm going to put the old one back on and see if that helps. I left the 2 connections unplugged all night so I'll head out in a bit to see if the battery is drained.

I need a different manual anyways. The Chilton my dad gave me with the truck covers 1976-86 pick-ups and broncos. I keep seeing a Haynes that covers 1973-79 Pickups and 78-79 Broncos so it will probably be more helpful.

 

Could be the voltage regulator but my money is on the alternator having a shorted diode bridge.
If you would like to see a REAL wiring diagram (Ford factory diagram) go to http://www.fordification.net/tech/wiring.htm . They don't have the '77 yet but for the charging system you can use the '76.