Alternator won't charge and reference wires are grounded

[Ryan Hubbard]

Originally Posted by snowball

Sorry for the delay, I missed any responses.

Yes. the battery goes flat and won't start. Battery is 6 months old. Once the battery is charged it will start up again. There is a light on the dash indicating the alternator is not charging. Volts are 12.1.

There are 3 wires that come out of the back of the alternator. 1 goes to a fusible link to the battery. the other 2 plug into the alternator. Removing the wires causes the voltage to go up to 12.8V.

If I take those 2 wires, plug them back, they lead to the top of the engine block and into a wiring loom. When I jiggle those wires, the light on the dash goes out and the voltage jumps up to 14.4.

You don't have a ground, you have a loose connection. The two wires you are talking about is a 12 volt supply to the alternator to energize the charging circuit and the other wire is for the alternator to measure the "load " on the system to adjust output. It looks like the wire that supplies voltage to the alternator is the one cutting out and effectively "shutting off" the alternator.