Author Topic: Alternator help! (again)(very long!)  (Read 945 times)

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SMC4WD

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Alternator help! (again)(very long!)
« on: February 01, 2006, 02:59:46 PM »
Alright, maybe not help...  Maybe some advice beyond the advice I was just given.

The friggin' Jeep alternator issue is not going away.  As mentioned in previous posts, it became as simple as the fuses.  Now someone mentioned that the fuses need some sort of power surge to blow them, but based on the wires, hook-ups and draws...   I can't see where an extreme power surge would happen.  (But I'm electrically illiterate, and that might have a lot to do with my issues).

So here’s what’s going on:  I have two gauges inside the cab.  Both are simple voltmeters…  One is connected directly to the battery, while the other one is the factory voltmeter, and come from where ever the factory wants it to.  
So the issue is that both gauges are reading low.  11 volts to be exact.  I checked the fuses, (Duh!) first thing this time!, and they were good.  So I got it home and put a battery charger on the battery over night.  I had to get to work the next day (10-12 miles) so I took the charger and an extension cord with me, but the gauges read 14+ volts.  I was working ok…   So I got to work, parked and worked.  I finished the day, proceeded to drive home, every looked fine halfway there, but the other half, gauges dropped again.  So I did the same last night.  Charged up the battery and this morning drove it into work.  This morning, the gauges were down.

This leads me to today, and the dilemma.  I left this afternoon to an alternator rebuild shop right up the street.  I brought in an old alternator for them to test out.  The brushes and maybe the armature needed to be replaced, but it was putting out full volts.  So then I asked if they could check the one in the Jeep (while on the Jeep).  He said that he could do it, and he did do it.  The alternator seemed to be doing ok (putting out volts), but my gauges were still registering low.   So he recommended pulling it out and checking it on the bench.  Sure!  I’ve got nothing better to do in a parking lot of an automobile electronic shop.  I hop on up and pull the alternator out.  We bench test it and it too was putting out volts, but the brushes were worst, and the bearings were a tad noisy.  So they came to the conclusion that it was the voltage regulator .  

Now, after all of that, here’s the help I need!!

Because the first alternator was in a bit better condition then the one that was already in the Jeep, I obviously switched them.  I hooked everything up, just like normal and (yup, you know what’s coming here…)  All the gauges read 14+V  

So what’s the deal??  The voltage regulator is in the ECM (stupid Chrysler).  I’m not replacing a $200.-$250. computer if I don’t have to.  I see an intermit problem.  
Where is the ECM?  Could a connection be loose?  All the connections of both alternators were that same, and they were both tight…

Where else should I be looking???  You know the saying, if it ain’t broke, don’t fix it.  Well as of now, it ain’t broke.  But come on, something’s not right!!

This is where the help part comes…   HELP!!!

Grundar32

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Alternator help! (again)(very long!)
« Reply #1 on: February 01, 2006, 08:21:29 PM »
my suggestion would be connections... check every dang wire that touchs that system clean your batt cables .. hit the connections at the back of the alt with a tad of sand paper and a cleaner if you have one....


 and i belive the ecm is that black box ..drivers side firewall under the clutch fill ... be sure to disconnect batt before playing with the ecm harness connector you dont want to spike it

roadkill

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Alternator help! (again)(very long!)
« Reply #2 on: February 03, 2006, 10:10:57 PM »
can't you just bypass the computer and run an external voltage regulator.  might be a lot easier than trying to track down electrical gremlins

SMC4WD

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Alternator help! (again)(very long!)
« Reply #3 on: February 03, 2006, 10:27:29 PM »
Quote from: "roadkill"
can't you just bypass the computer and run an external voltage regulator.  might be a lot easier than trying to track down electrical gremlins


I totally thought of that.

It's still running and charging, so as it stands...  
"If it ain't broke, don't fix it!"

I mentioned in the Nissan post, I'll try to clean up the wiring and see where that takes me.