I have an 87 f150 that the alternator was disconnected. The previous owner just cut the wires. How it should be connected?

For what I know:
Blk/org +12V battery (both)
Yel/wht +12V (with the blk/org)
Wht/blk to wht/blk on regulator

And grn/red to indicator. What does this wire do? It is the ground for the regulator, or should be connected to +12V?

Please help with this. If I don't want to connect it to the indicator (instrument cluster and fuse box problems) where it should be connected?

 

The green/red brings the alternator "online" with the keyswitch. If you did not have this wire with this function, the alternator would run the battery down when the engine was not running.

The indicator light is a handy thing to have. If you throw a belt, or have any sort of charging problem, the light will light up instantly giving you a alert.

Originally the power came from the keyswitch, ran through one side of the ungrounded light, and exited the other side of the light and ran out to the green/red to trigger the alternator. They usually had a resistor that also bridged the bulb, so if the bulb burned out, the charging system would still charge.

If you do not want to run a light, just hook the green/red to a key on power source. But I strongly recommend you get a light of some sort, and hook it up in series with this wire as a indicator. Just make sure the light you get is ungrounded with two leads.

 

Thanks.

The thing is that I bought an f150 that has electrical problems and the wiring is a mess. A lot of wires where just cut. I put new universal ignition switch with new battery, ignition and starting wires. Connect the alternator wires (also were cut) as mentioned above. It was charging, proved with a multimeter and also the voltage gauge in the cluster is functioning. But right now it is not working properly, is not charging.

When I first conect everything it gave me some 13.5-13.7V when running. Right now I just have 12.5V, just battery voltage.

 

I still having problems with the alternator. Again, I connect everything as previously said: the blk/org and yel/wht to battery, wht/blk one to each other, and green/red to indicator.

The thing is, when no using it I leave the battery disconnected; when I first start the engine the alternator charges givin like 13.8V, then I turn it off but when turn the engine on again it just dont charge. If I left the battery disconnected until the other day, the story just repeat. Start charging then no charge.

I tried almost everything, disconnecting the alternator from battery, then turn the engine on; disconnecting just the grn/red wire, grounding the alternator first, etc etc etc.

Please help me with this. I need help...

 

When the engine is running, and it's not charging, take your meter and take some voltage readings. You should have;

12v on the large black/orange output wire

12v on the yellow/white wire

12v on the green/red wire.

I still suspect you have problems with the green/red wire the way you are describing how it's acting. Take a jumper wire and go from the bat + to the grn/red terminal and see if it starts charging.

 

I already did that. Yesterday I did it again; also I cut the wire to isolate it from the gauge cluster. Within the week I will buy another alternator, with regulator and everything. That's the only thing left to do.