EEVEE

Hello. I recently just changed my electric cooling fan with a new one from rock auto. It looks slightly different and one less blade but it works and does its job but i finally noticed my voltage is kinda lower than it usually was because this is the first time of really driving it in the dark as its been pouring rain and dangerous outside. I dont know if thats how bad my old fan really was because it usually stayed a smidge under 14 now its that low. Is that normal? This is with headlights, aftermarket fog lights that pull 50 watts and ac on full blast. I just dont remember it being that low before. I have been going through some deep water in florida and flooded roads and i know i dont have a splash shield underneath. Did i do damage to my alternator?

Edit: i forgot to mention it does come back up to around 14 when i rev my engine up a bit and drive.

BlueRidgeMark

Not normal. Verify with a meter before you start troubleshooting. Might just be the gauge. Might be a dying alternator.

tech

Check the battery it may be weak that can also give s low gauge reading .

nujeepguy

voltage is set by alternator regulator when batt is charged .

moparado

Headlights on + Fog lights on + AC on + blower on high + elec.fan on = ~12 Volts @ IDLE

The alternator 'at idle rpm' is not supplying enough power to charge the battery under all that electrical load.
A battery voltage drop is typical with high electrical and mechanical loads at idle rpm.
But 12 volts would be troubling at idle.

Does the engine rpm drop significantly when all that stuff is turned on?
Engine idle run rough?
Do you hear the belt squealing?

First check to see if the belt is slipping under the alternator and AC mechanical load. It might need tightening or even a new belt.

The AC compressor could also be going out presenting a higher mechanical load than normal causing the engine rpm to drop.
Also when the AC is turned on, the PCM increases engine idle rpm to compensate for the increased AC mechanical load. Could be a sensor issue.
Or it could be something as simple as your alternator is 'tired'.
Try shutting off all those things one at a time to see which has the biggest impact on the low battery voltage.

Alternator amperage output ratings are typically rated at a much higher rpm than idle rpm.
If all checks out ok and especially if you drive a lot with all that stuff turned on, last resort is to replace the alternator with one that has a higher amperage rating.

EEVEE

Oops i should have been more thorough with the details. Yes there were ALOT of things going at that time, Ac at full blast, wipers on high, rear wiper on to see and also i must of not noticed it but i also hit the rear window heater too, in reverse (that seems to put a slight load on my stuff) with the brake lights on, all the previous stuff mentioned and my dome light on and my friend who loves to shove stuff in my jeep without thinking a box was pushing the rear window button up but once i turned the window heater off and the dome light and all the other crap it now typically hovers on the line below 14. Maybe it was just that random ocd thing and moment it went that low and my eye caught it and snapped a pic when it was on all that load.

EEVEE

eh maybe i do have something up lol. Went to start it today after sitting yesterday and it was dead.

BlueRidgeMark

Told ya.

EEVEE

The people at the auto part store said it sounds like a ground issue. They put their tester on it and tested both battery and alternator and they said everything came back fine.

kemjeep

did the auto parts store put a stress test on alt. such as you did that night? if not just a meter might not show an alt. on its way out dont worry when you least expect it you will get your answer now my 2cts. if battery is relatively new I vote alt. on its way out

BlueRidgeMark

1. Most people working at the average auto part store don't know their backside from a hole in the ground.
2. Can't hurt to clean up your grounds. It never hurts to clean up your grounds.
3. Make sure you check the integrity of the battery cables, especially that ground to the fender well.

EEVEE

I typically take their word with a grain of salt as well lol. I kinda believed most of this guys words as he did also owns a cherokee of my style and he said the grounds if they have never been check might not be grounding well. And his problem before was a wire on the starter came loose and throwing everything off. Might i ask where are ground locations? Im new to working on my own cars and have no clue where to even begin looking. And tbh im going to a different store as they of course sent the noob to test it and i suspected he screwed the test up as he said my battery didnt show the cranking amps so he stuck 500 in the machine. And he made me cringe on the alternator test as he didnt slowly rev my engine up nope half throttle basically and made it hang at 4k rpms which made me grind my teeth and worry but it said it passed but the battery test passed as well but im ruling out faulty info. But the noob went to the back of the store and i talked to the older guy that had the jeep and told me about the ground stuff. And i have a battery from rural king. Its about 3 years old but seems to crank fine nonetheless. Then again i can be wrong.