[VetteVet]

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Originally Posted by CST10

Ok, my alternator went out yesterday on my 1970 C10. I ordered a new high 150 amp alternator from powermaster. I can't seem to find an answer on the website or here so.......it's going to be a 3 wire hook up with the sensing wire.

I ordered the alternator to battery larger 6 gauge cable at the same time.

Do I hook this wire to the current battery junction box on the firewall that the old system used with the fusible linkage? Or go straight to the battery?

Question is, do you have the 7 gauge dash or the 3 gauge with the charging light? If it's the 7 gauge do you want the ammeter to work?

Do I need to upgrade the fusible link? If I go straight to the battery, what would I use as overprotection so I don't blow up the battery or some crazy stuff?

You only need enough power to keep the battery charged so you don't need a big huge cable or a large fusible link 40 amp is plenty. Everybody seems to think that the battery supplies all the power to the truck and the alternator just recharges the battery. In fact the alternator runs everything and recharges the battery. The battery just starts the truck and supplies emergency power if the alternator fails.

Anything else I'm missing?

You'll need a junction block to run the 6 gauge wire to ( I used 8 gauge ) and the sensing wire. The exciter wire from the alternator must run to the key switch through a 10 ohm resistor wire which you should already have from the key switch to the firewall block. It will exit the firewall block on the engine side as a 16 gauge brown wire, which ran to the old external regulator.

What about ground cable systems?

Battery negative to engine block. Engine block to front frame, and one to cab. You should have a ground from the neg cable to the radiator support shroud for the front lights. 10 or 8 gauge. Then the back bed to frame ground, and make sure the fuel tank is grounded. Inside the cab the dash
must be grounded to the instrument cluster. And the wiper motor must be grounded to the cab. Anywhere else you want you really can't have too many grounds. There is a grounding diagram somewhere, I'll see if I can find it.

Anybody have some diagram?

I like this one.



Don't wanna fry the truck down.

Thanks.