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Unread 01-16-2011, 05:39 PM   #1
wisteriaaa
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1995 YJ Wrangler 
 
Join Date: Dec 2010
Location: Portland, Oregon
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Need new alternator?

My power gauge jumps whenever I turn on heat/ac/lights. It goes up and down on a whim, which is leading me to think the sensor is broken. I went to a battery place and my batt is healthy. I've seen some people use other model chrysler alternators that put out more power and cost less. Any ideas?

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Unread 01-16-2011, 06:21 PM   #2
laybackman
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Quote:
Originally Posted by wisteriaaa View Post
My power gauge jumps whenever I turn on heat/ac/lights. It goes up and down on a whim, which is leading me to think the sensor is broken. I went to a battery place and my batt is healthy. I've seen some people use other model chrysler alternators that put out more power and cost less. Any ideas?
Mine does the same thing. The gauge is a little 'touchy' but it is no big deal. To field test your alternator - At night with your headlights on.... Note their brightness at idle now pop a rev. They may get just a bit brighter and not change much when the engine drops back to idle.
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Unread 01-16-2011, 06:22 PM   #3
laybackman
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Quote:
Originally Posted by wisteriaaa View Post
My power gauge jumps whenever I turn on heat/ac/lights. It goes up and down on a whim, which is leading me to think the sensor is broken. I went to a battery place and my batt is healthy. I've seen some people use other model chrysler alternators that put out more power and cost less. Any ideas?
Mine does the same thing. The gauge is a little 'touchy' but it is no big deal. To field test your alternator - At night with your headlights on.... Note their brightness at idle now pop a rev. They may get just a bit brighter and not change much when the engine drops back to idle. That is normal.....if anything is normal for a Wrangler!
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Getting older, I have developed some special skills. I have the ability to cough, sneeze, fart and pee at the same time.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
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Unread 01-18-2011, 11:36 AM   #4
wisteriaaa
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So i did the test, and sure enough the voltage gauge bounced back and the lights/heat got much brighter and blower motor was faster. Should I just get a replacement 90A alternator? I've seen lots of people here talking about getting grand cherokee or wrangler sahara 120A alternators and installing the with no problem. I have the 4.0L engine.
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Unread 01-18-2011, 11:56 AM   #5
Big4mike9
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Unread 01-18-2011, 04:10 PM   #6
laybackman
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Quote:
Originally Posted by wisteriaaa View Post
So i did the test, and sure enough the voltage gauge bounced back and the lights/heat got much brighter and blower motor was faster. Should I just get a replacement 90A alternator? I've seen lots of people here talking about getting grand cherokee or wrangler sahara 120A alternators and installing the with no problem. I have the 4.0L engine.
Now, before you go ripping out and upgrading your alternator the next big question is; What condition are your battery cables and cable ends? Just because they look OK means nothing. If they are original I would toss them out and replace them all.

They are probably loaded with green corrosion under the insulation. That sets up high resistance. This high resistance can reduce the amperage output of an alternator and causes dimming lights and large swings in the amp gauge readings plus premature death of your alternator.

Think of corrosion as if it was a choke hold, cutting off the free flow of the electrons along the copper wire surfaces right where the corrosion resides.

Disconnect both battery cables and lock onto each battery post connector with a pair of vise grips. Now twist each wire at least one full turn in each direction three or four times and then hook them back up. Now run the same field test I mentioned earlier.

Did you see any improvement? if you did then your wires are all crappy inside and need replacing. And your alternator may be alright after all!
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Getting older, I have developed some special skills. I have the ability to cough, sneeze, fart and pee at the same time.

"If we cannot afford to take care of Veterans, then we should stop making them."
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