General Maintenance & Repairs - Voltage @ Idle

Hey LS1 F-body owners, I've got a poll ^^^ for you: When you are idling (car warmed up) with the ventilation fans on full HIGH (setting 4), does your voltage gauge dip?

Mine will drop to just above the orange zone on the low side ~12v until I start moving again (~14 volts). As a result, the vents move less air and the blinkers slow down. If I recall, in the winter if I have the vents on high, the defrosters on, and the wipers running, I can get the needle down to the orange but I think the car will do something to push it back up, probably raising the RPMs.

I'm guessing this means the alternator is going. From underneath the car on the driver's side I've noticed a flat, green, shoelace-like grounding strap which I think originates above the alternator. It is so hard from age that it is broken off and I have no idea where it was originally anchored to the chassis, and I haven't traced the other end. Any chance this could be the cause? Can anyone check for me where this braided cable is supposed to go? Thanks.

Just for the record, your voltmeter can be wrong. You need to get out your multimeter and test at the alternator and battery for proper voltage. With my 95 LT1 M6, I can have the fans going on high, subs cranked to the max, volume up, cranking my rock out, all stock lights and aftermarket fogs on, vents on high, basically a full load minus A/C since mine isn't operational, the voltage doesn't drop below 13 on the gauge and reads higher on the battery. Admittedly, I idle at 1000, so that may have something to do with it. So check the battery w/ a multimeter first.

truck alt FTW !!!!!!

this^^^ before i had the the truck alt the stock one would go right between the red and 13 mark just idling now with the 130 amp with a full load it never dips below the 13 mark

Any recommendations on an alternator model or store in which to buy it?

Mine dips when warm below 12v with ac on and I have a Power Bastards 220A with an overdrive pulley. When cold it reads way high on the voltage gauge but at idle (550) it dips just like stock. Once I clear 600-700 it reads over
13 again no matter the load. It doesn't offer full output until 1250rpm tho. Best thing is to raise the idle up 100-200 rpm.

This is normal and not necessarily indicative of a "problem." If the voltage is above 12V you can forget about it.