A daily driver, fixer-upper thread

[Lugnut64052]

So I sorted all that out, got it straight in my head, then started looking at how to further upgrade to the CS alternator that came with the ’95 serpentine drive. The factory plug on the CS contained only one wire, which was, appropriately, a brown one.


Here’s the pin assignments for the CS:

"P" Not used.

"L" Hooked to key power (a switched ignition source). Turns the regulator on and connects to the original brown wire. If this circuit has a dash warning light, you're fine. If it doesn't you need to wire a 35-100 ohm, 3+ watt resistor into it or it'll bake the regulator.

"F" Not used.

"S" Voltage Sensing wire. Connects to the red wire splice, or in my case, the added junction block on my firewall.

ACDelco makes an adapter harness to go from an SI to a CS. P/N is 8078. Long GM P/N is 12102921. It has the resistor built into the "L" wire. Delco also makes an adapter without the resistor. I cut the "SI" end off and spliced it into my harness. Evidently the regulator inside this CS is sensing power right in the alternator, hence the one-wire original plug. I hooked up the remote sensing feature anyway. A replacement one may not be internally wired the same (edit: looks like it's remote sensing now, since I enabled that circuit).

The result: a steady 14.3 volts across the battery at idle. Works great.