JDMSteven

So I've been having problems with my ES and its pretty upsetting. I even ended up buying an alternator when I probably didn't need one but oh well. Battery also tested good from Walmart.

When my car is at idle with the lights on, and radio, I'm getting 12.5v, but the second I cut on the A/C, it drops way below 12 and will kill the car in 10mins.

Idk if I should link this problem to the A/C or something else. I've checked all my fuses, including my 100amp alternator fuse and they're all good. Cleaned up my ground connections and terminals and still no changes.

BDSL

When you said "...will kill the car in 10 mins", did you mean the engine will stall in 10 mins with the AC on? Is there belt noise (or any noise) when you turn on AC? Does the engine rpm jump up a little bit?

JDMSteven

The engine will die from lack of electricity lol. And there is a loud noise that sounds like it could be from the timing belt (which occurs all the time, regardless of AC) but the timing belt was changed at 120 and im at 144. When I turn the AC on it drops about 500rpms

Oro

It sounds like the voltage regulator in the alternator is DOA.

This is not uncommon on newly rebuilt units, particularly from Autozone, or 2nd hand non-rebuilt units.

The rpms drop momentarily, or stay there w/the A/C on? A momentary drop is to be expected.

JDMSteven

Yeah I understand where you're coming from, I've had to replace an alternator 3 times on my truck before I got a good one. This one was bench tested though before they even gave it to me and its good.

RPM's stay low, if I turn it off it comes back up just fine.

BDSL

Maybe seized AC compressor

Oro

I am unclear, then, how you are reconciling these two statements?

It is possible your battery is good and your alternator is good, but to get these results you then need a bad ground strap or some other gross error in the very simple wiring between the units. And you say that has been checked and is good.

Fix the basics and set a baseline before tearing at other issues or throwing parts at it. a/c on should not affect charging voltage.

Sounds like you have an a/c issue, but there's something else basic going on here to address first.