This has came up a few times in the past with converting to factory gauges. I know the Pontiac guys reallyhave no issue with it as their volt gauge has a warning light in it. From the time my Monte was on the road (& still assembled) after I did the conversion ('93 to '10) the car never had a charging issue with out using the resistance wire (130) that ran from the bulkhead connector to the Ignition 3 (300) on the ignition switch. It just had the circuit (25) run complete/unaltered to the cluster plug where the wire still sits at this point. I have a doner harness that has it in it & wonder if it'll be worth it to add it in, leave it be, or convert the Check Engine light into a alternator warning light. The other thing is what real purpose does it serve if I'm not having any issues with out it. Does it keep the volt gauge from flicking when the turn signal are on (seen this on conversion & aftermaket gauges). Despite everything I've learned over the near 29 years having the car, that wire/circuit I don't fully understand it's purpose.