Dummy Light to Gauge dash swap chaos! Help?

[VetteVet]

Originally Posted by 67stepchic

So I have a 67 c10 that has butchered wiring like you wouldn't believe. After some bad info on dash lights I fried the printed circuit from the original dummy light cluster. So, am replacing it with a gauge cluster out of a 70-72 model c10.

I've read GMC Paul's write-up, and a few million other Q&A's...

My problem is wiring of the alternator and battery to the respective #1 and #12 slots on the loom plug...

1. I have no junction block
2. This truck was in some way converted to an internally regulated alternator when the PO also did an HEI conversion

So where do I get these wires from so that my gauges read properly? Any help would be great!

Here is the way the factory wired the gauge trucks. The junction block you say you don't have is just a soldered four way connection in the harness. This may have been chopped out somewhere along the way.

You will have to have the 4 amp fuses in the wires to protect the gauge and you have to connect the wires to the alternator and to the battery but you cannot run the alternator directly to the battery or to the starter terminal. You have to have a shunt wire between the alternator and battery connections. If whoever converted your alternator ran the alternator output wire directly to the battery then the gauge won't work.

Study the diagram and you can see the connections and the shunt.



Here is the junction on my truck which has the idiot light dash so I will have to connect the ammeter wire there. I suppose it can be connected right on the alternator as long as the alternator wire doesn't go directly to the battery.



There is supposed to be a junction bolt on the right inner fender by the battery. This is where the fusible link from the battery and one end of the shunt wire is supposed to go. That is where the other gauge wire goes.