Starter and Alternator wires

[Rooster73]

Looking for some help or at least a direction to go to find an answer. I picked up a '79 GMC k1500 Suburban. The previous owner started to pull the engine out and then gave up. The wires to the starter and to the alternator were cut. I'm not sure which wires and how many wires there should be and where they all go to and come from. I'm finding lots of wiring diagrams online, but they are confusing to me, or they conflict with each other.

Another question related... Can I solder in splices or am I going to have to pull new wires? I'm not sure if any of these wires will have fusible links and if they do, I'm not sure if they've been cut out too.

Any suggestions or direction where to find this information?

Thanks.

 

[Ricko1966]

Did they cut all three wires to the alternator? Starter should have two wires with fusible links going to the main post along with the positive battery cable. A purple wire going to the s terminal on the solenoid. Alternator needs 1 wire to feed 12 volts to the battery from the B+ terminal a brown wire to terminal 1 to work dash light and as exciter wire. Third wire is voltage sensing wire. Is the harness still in the truck and are the cut pieces? I can't imagine someone would cut them and disconnect them,so I'm thinking all the wires should be there. This should be a simple splice it back together situation,or splice on extensions where the harness was cut sitiation

 

[Rooster73]

The cut off portions on the starter are gone. The starter was sitting inside the cab. The alternator was gone completely. I think I’ll be good to splice some sections in. I just wanted to make sure the right wires were there and I wasn’t missing any fusible links or anything. I haven’t done much rewiring so I’m not experienced with what wires exactly go where. The other square body I have the wiring is kind of cobbled so it’s not a great reference.

The harness is still in the truck. It’s almost as if they just cut the wires when removing the starter and alternator. Weird. Not how I would have thought anyone would remove the starter or alternator.

 

[75gmck25]

Your truck is probably wired exactly like my '75 and Rick1966's '75.
One quirk is that you may have an extra wire on the starter that runs up to the wiring loom for the in-dash ammeter (ammeter was used up through about '76). This wire has a small fuse in the harness, usually in the wiring above the passenger side valve cover.

The in-dash ammeter gauge shunt has one side connected to the full 12 volt side of the wiring at the starter, and the other side of the ammeter shunt is connected to the power junction near the brake booster. The difference in voltage between these two points is used to calculate the amps displayed on the gauge. Kind of kludgy, since an ammeter shunt needs to have a known resistance to be effective, and I'm sure the resistance of the wiring degrades over time. However, it's better than running the full amperage up and through the dash gauge.

 

[mano]

I don’t know if this will help you out or not. These pics are out of a K 10 1979. After going through four different alternators, I went with the tough stuff, one wire alternator, and haven’t had any problems since. Just ran the one wire right to the positive side of the battery.