Yet another Carbed ls alternator Question

[lt155ruck]

Sorry in advance to everyone that has ever read or replied to the thousands of these questions. I have spent Hours reading and now am more clueless than before I started reading.... The motor is in and it seems all the fiddly Bs is taking FOREVER.

This is the scenario. 1972 2wd Blazer with a vvt deleted ly6 6.0 that is CARBed and a 700r4. I'm using a truck alternator with the 4pins. From what I THINK i understand "S" and "P" will remain unconnected. "I/F" will go directly to a switched 12V source and "L" will go to either an idiot light or a 470 ohm resistor. The other side of the bulb/resistor will go to a switched 12V source.
my questions are

1. Can i connect the brown wire from the original Blazer harness that was originally going to alternator to the ''L" ? will this illuminate the alt/gen light in the dash? I've read conflicting posts that the light stays lit all the time? can anyone confirm this? or dispute

2 What is everyone using as a switched 12v source to power both the I/f and L terminals? Is there something I can tie into under hood? maybe the original voltage regulator?

3 what happens to the other wire from the stock Blazer harness that goes to the original alt? is that a switched 12v source that i can tie into.

Again I'm sorry for making you read yet another question on this but i really need clarification specifically for my 72

[lt155ruck]

Sorry guys the two colors in the original 1972 alt harness is yellow and blue/green

[SoMsippi_B-tie]

I posted this over in another LS Alt thread a while back. The reason I posted is because I am assuming you still have the original wiring harness and it really isn't rated for a higher output alternator like what comes on these LS motors. I'm sure folks have done it and haven't had any issues, but I would side with safety...... Also, the plug 30705 from painless shows how to wire up the CS130D alternator. You should also not be using the voltage regulator that came on your truck. The LS alternator will sense and regulate the power that is needed.



I have a 69 that had original harness in it and swapped to 5.3 with carburetor. I spent a few hours reading and studying about how the older style OEM wiring harnesses and the chevy alternators actually work on the older cars/trucks on this site http://www.madelectrical.com/electri...evymain1.shtml

What concerned me was that I just spent all this money to upgrade my truck, but would also be running 2 electric fans, and 1 electric fuel pump off of my battery and possibly have too high of an amperage draw and too high of an amperage output alternator and an undersized wiring harness that was almost 50 years old. Rather than taking the chance of being stranded or burning my truck down I switched to a painless wiring harness and that kit comes with the stuff you need to properly wire a 105 amp (max allowed) type CS130D alternator and make your electrical system operate off of the power output of the alternator and properly sense the voltage draw of your electrical system and charge the battery as needed. I also had to buy the plug, #30705, from Painless for the alternator so that it could be properly wired. It took several phone calls to Painless to get the right person that understood all of this and knew what I was asking, as well as what they were talking about. Also, their wire harness instructions were being revised, and at the time I downloaded this particular wire harness instruction manual from their site it had not been updated and it did not explain anything related to the newer style CS130D alternators, but the one I received in the box with the harness was the correct set of instructions and described all of this to the letter...... I also tried to talk to Holley technical because they sell a LS alternator and plug, but I could never get the right person that actually understood me or their product on the phone to help me understand how to wire it up to an existing harness, therefore I chose to go thru the effort of swapping the harness out and do not regret it.

It's worth your time to read up the explanation of how a proper charging system works on www.madelectrical.com

[lt155ruck]

Thanks for the input, I'll spend some more time reading the link you attached