alternator problems?

STINGN · **Posted:** Thu Nov 25, 2010 2:38 pm

My battery light just came on last night after I filled it up. Windsheild wipers were going really slow, lights seemed dim also. My question is how can you test yourself if it is the alternator or the battery? I am currently charging my battery to see what happens. But if it ends up being the alternator, I will get a new one. Question is, which one should I get?

Advanced has a 136 or a 160. I am guessing with extra lights and sound system I should get the 160amp if it is my alternator that is going bad.

Thanks, Steve

STINGN · **Posted:** Thu Nov 25, 2010 4:46 pm

so i charged the optima all the way. started the jeep, and the volt meter read the same thing while it was running, which leads me to think that it is the alternator

tjkj2002 · **Posted:** Thu Nov 25, 2010 4:49 pm

STINGN wrote:

so i charged the optima all the way. started the jeep, and the volt meter read the same thing while it was running, which leads me to think that it is the alternator

Or the PCM is bad as the PCM houses the alternators voltage regulator.

Every Chrsyler I've ever worked on that is a '00 or newer(TJ's not included) and has had zero voltage from the alternator has been a bad PCM as the voltage regulator is the 1st thing to go out in a alternator in most cases.

Oh and to test for that you will need a DRBIII,if '06 and newer you will need the StarScan.Autozone or advance can not test your voltage regulator.

STINGN · **Posted:** Thu Nov 25, 2010 6:43 pm

Would buying a new alternator fix the pcm problem or is that a separate part? If it is where can I buy a cheap one?

STINGN · **Posted:** Thu Nov 25, 2010 6:59 pm

I didn't check the volts on the alt, I just check battery and decided to just get a alt because it was cheap. And concidring I have 80k on it, I also have extra lights and subwoofers. So I'm hoping the alternator solves the trick. If not, then I shall ask more questions.

Albert · **Posted:** Thu Nov 25, 2010 7:59 pm

STINGN wrote:

I didn't check the volts on the alt, I just check battery and decided to just get a alt because it was cheap. And concidring I have 80k on it, I also have extra lights and subwoofers. So I'm hoping the alternator solves the trick. If not, then I shall ask more questions.

Which alternator did you get?

Note............The 136 was OEM standard on Sports and Limited and the 160 was OEM standard on the Renne due to the extra roof lights. That was why Autozone had both listed. They should have told you that at Autozone. Pretty sure that is the difference. Troy or one of you professional mechanics can correct me if I am wrong.

:JEEPIN:

tjkj2002 · **Posted:** Thu Nov 25, 2010 8:36 pm

STINGN wrote:

Would buying a new alternator fix the pcm problem or is that a separate part? If it is where can I buy a cheap one?

No if the regulator is bad you need a new PCM,and the PCM will run about $400-$600 plus what it costs the dealerhip to program your VIN into it.

Good luck with a alt bought at advance,you will need it.

STINGN · **Posted:** Thu Nov 25, 2010 9:09 pm

well, i unplugged the battery while running and it turned off about 3 seconds after i did that. ugh, i just want the new alternator to come in so i can hook it up to see if i am doomed!

liquidxit2 · **Posted:** Fri Nov 26, 2010 12:40 am

Did the lights get brighter when you hit the gas? Usually that's the tell tale sign of a bad regulator. Also it won't hurt getting a new one anyways and def the 160.

STINGN · **Posted:** Fri Nov 26, 2010 1:31 am

they kind of stayed the same. but the wipers were slow and the windows were really slow

Zack A · **Posted:** Fri Nov 26, 2010 2:10 am

I wonder if the rocky mountain edition came with the 160 alternator? I'm in the same boat. Off road lights, sub and some emergency lights.

kskj · **Posted:** Fri Nov 26, 2010 2:15 am

Seems like I have read on here somewhere that if you do not have the Rene a 160 alternator will not be any better because the regulator will keep you at 136 amps on the sport and limited.

liquidxit2 · **Posted:** Fri Nov 26, 2010 2:56 pm

STINGN wrote:

they kind of stayed the same. but the wipers were slow and the windows were really slow

You probably do have a bad alternator. Most regulator issues I have run across have been slightly dim lights and increase in brightness to normal with throttle. Either way with the dea you got on a 160amp it isn't a bad idea. Now I cannot say with 100% certainty that your regulator is fine but I'm 95% certain for a forum diag that is.

Sent from my SPH-D700 using Tapatalk

STINGN · **Posted:** Sat Nov 27, 2010 10:45 pm

well...i put in the new one and still got the light...got pissed. started to :banghead:

and it gave me this :dizzy:

...so then i went back and check everything under the hood. The PCM was clean, no corrosion. Check. Then I looked at the voltage meter. Was going from negative to ground, 0 volts. then the negative to the alt, got voltage, bingo, found my problem. The battery wire to the alternator was not grounded properly and i just had to clean the ground to the frame and then tightened it. No more problems..on the bright side, i got an alternator with almost 3x as less miles on it as mine! (so no more whining noise either)

alternator problems?

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