Ls alt wiring

[mattcrp1]

Sorry, I have a 2002 4.8l in my 1976 SWB. The 2002 appears to be "self contained" as far as what I need to do with integrating the 1976 and 2002 harnesses. I also have a question as to the blue oil pressure switch wire from the '76 harness as well.

[ls1nova71]

Originally Posted by mattcrp1

Sorry, I have a 2002 4.8l in my 1976 SWB. The 2002 appears to be "self contained" as far as what I need to do with integrating the 1976 and 2002 harnesses. I also have a question as to the blue oil pressure switch wire from the '76 harness as well.

You can just eliminate any of the original '76 alternator wiring, it is self contained on the 2002 like you said.

As for the blue wire for the '76 oil pressure gauge, you need to mount the '76 oil pressure sender in either the oil pressure sender spot of the 5.3, or you can drill and tap the block off above the oil filter, then just hook the blue wire to it and you're done.

[Pzary3233]

Originally Posted by mattcrp1

Sorry, I have a 2002 4.8l in my 1976 SWB. The 2002 appears to be "self contained" as far as what I need to do with integrating the 1976 and 2002 harnesses. I also have a question as to the blue oil pressure switch wire from the '76 harness as well.

You will not use any of the wiring from the original 76 truck except for the GEN light which will be needed to put a slight resistance on the wire.

Assuming that you have a truck alternator this is what you need to do - Copied from what I posted on the first page:

One wire goes straight to 12 volt (Pin C), the other MUST have resistance, ie gen light or resistor (Pin B)..





However as LS1Nova pointed out you can easily just leave the two wires connected to the PCM and let the PCM worry about the Alternator

Originally Posted by ls1nova71

You can just eliminate any of the original '76 alternator wiring, it is self contained on the 2002 like you said.

As for the blue wire for the '76 oil pressure gauge, you need to mount the '76 oil pressure sender in either the oil pressure sender spot of the 5.3, or you can drill and tap the block off above the oil filter, then just hook the blue wire to it and you're done.

This is correct, you need to use your original sending unit, or another sending unit that fits in the LSx with the same output as the original 76 sending unit.

[ls1nova71]

Originally Posted by Pzary3233

One wire goes straight to 12 volt (Pin C), the other MUST have resistance, ie gen light or resistor (Pin B)..

This is correct if you are NOT running it through the PCM (with a carb, for example), but, if you are going EFI, just let the PCM control if and nothing has to be done with it. Even if your truck has a GEN light, which I just assumed it had a voltmeter (we all know about ass-uming ), I wouldn't use it.

As for a mechanical oil pressure gauge, check my build threads, at least one of them shows how to easily fix that with a drill and a tap. Super simple.

[Pzary3233]

I answered your question just a few posts up:

DO NOT USE THE C10 WIRING it is too old and small to handle the amperage! Sounds like you have a handle on that part. You may use the idiot light wire (because you do need an idiot light to make this alternator charge). Simply find the wire that is connected to your idiot light in the dash and follow this post and you'll be charging in no time!

Originally Posted by Pzary3233

You will not use any of the wiring from the original C10 truck except for the GEN light which will be needed to put a slight resistance on the wire.

Assuming that you have a truck alternator this is what you need to do - Copied from what I posted on the first page:

One wire goes straight to 12 volt (Pin C), the other MUST have resistance, ie gen light or resistor (Pin B)..