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Discussion Starter #1
I was on my way home and the Check Engine light came on. I checked all the gauges and noticed my Alternator gauge wasdown to the low side Most of the time its 3/4 ofthe gauge by the time i got home it was pretty low. Thiw was at night with all the lights and heater on. I turned everything off and the gauge still stays near the 8volts.


Everything else seems fine.

How much do Alternator run for my truck? can i get an upgrade higher amp maybe?
 

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Before you spend money for a new one have it tested. The ECM regulates it and I think the ASD relay on the fender well may also have something to do with it charging. You can bypass the ECM and put a regulator from a older dodge on. If you find thats your problem go to top of the page and google ( how to put external regulator on 1st gen.) Should be able to get your info. that you need.
 
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Discussion Starter #3
Before you spend money for a new one have it tested. The ECM regulates it and I think the ASD relay on the fender well may also have something to do with it charging. You can bypass the ECM and put a regulator from a older dodge on. If you find thats your problem go to top of the page and google ( how to put external regulator on 1st gen.) Should be able to get your info. that you need.
Thanks! Well its not the crank sensor or the PCM from what i was reading because the Trans shifts just fine Over drive works as it should. I will swap my ASD relay with the A/C relay and see if that helps..if not I will pull the ALT and have it tested
 

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Just because your OD still works doesn't mean the regulator in the ECM is good. You'll find out when you do your other checks.
 

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Discussion Starter #5 (Edited)
Well I swapped the ASD and the AC relay to see if t hat worked and nope still no charge. Next pull the alt and have it tesed at parts store.

I had a guy tell me to start the truck and pull; the pos cable off and if it dies it's tha ALT but from what I have read it could be a few things. So my best bet is to get the alt tested
 

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Does the 92 have an external voltage regulator on the firewall? I know my 89 does and had to replace it once. Usually if the regulator goes out it will overcharge the battery and eventually stop charging altogether.
 

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Blayner is right: the next step is to pull the alternator and have it tested.

If you are doing +8 vdc you know the charging system isn't working and the alternator, voltage regulator (inside the ECM), or wiring is the problem.

Roy
 

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Interesting in that I have the EXACT same problem as of this morning. My system was not charging, and I got the "check engine" light. The scan tool shows it was code 41 "alternator circuit." There is no voltage to the alternator, so I do not believe the alternator to be the actual problem, but rather the voltage regulator in the PCM, or the crank sensor. I'll check back when I figure it out.
 

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Discussion Starter #11
Mine is still down. I didnt have time today my sister inlaw had a baby and the wife has been gone all day and i have my Kids....so no working on the truck. My son likes to help but my 3 month dont understand...LOL

Keep me posted on your find
 

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Discussion Starter #12
Well i pulled the Alt off had it bench tested and it was not charging this was at Auto zone and then went to Napa they same results. So i guess I am getting a new ALT:confused013: But like i said when Autozone scaned it on the truck they said reg was bad:confused013:
 

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First, I'd suggest you teach your 3-month-old to yank alternators, starters, and so forth. I mean it is not like you're asking him to diagnose the problem.

One used to buy rebuild kits for alternators: brushes, bearings, diode pack. I bet they are hard to find now, but might be worth checking. How many miles on the truck? It could just be the brushes. At 200k my alternator front bearing went totally south w/o warning that I could detect.
 

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Discussion Starter #14
LOL the 3 year loves to help. Look what came today sure it would come today now that I have the truck apart...LOL



 

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dude sam thing happened to mine and it was he alt. that went bad hold on to your shorts if it has the denso alt. if i remember around or a little over $300 took mine to the local interstate battery shop and had it rebuilt and am shure it has better parts and worksmanship than a typical parts store reman... and for what they charged me it was not worth my time to rebuild it myself plus i was out of town for work
 

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These alternaters are extremely easy to test on the truck. And you'll know that no one is snowing you at the parts store.

Test for battery voltage at the large pos terminal on the alt. Two small wires on the back of the alternater. Disconnect the two wires. Feed batt voltage to one terminal and ground the other, doesn't matter which. Start it and check your voltmeter. If it charges, should hit 14v and keep climbing depending on how low your battery is.

Steve g
 

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Discussion Starter #17 (Edited)
Reman one at Auto Zone is $119 with Lifetime warranty Local repair shop wanted $90 to rebuild it...said it needed a rectifier and brushes. I went with Reman from Auto Zone. I will get it put on this weekend along with my Denny T pin and 3200 spring
 

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These alternaters are extremely easy to test on the truck. And you'll know that no one is snowing you at the parts store.

Test for battery voltage at the large pos terminal on the alt. Two small wires on the back of the alternater. Disconnect the two wires. Feed batt voltage to one terminal and ground the other, doesn't matter which. Start it and check your voltmeter. If it charges, should hit 14v and keep climbing depending on how low your battery is.

Steve g
According to AllData, one of the small wires is 12V, and one is field.
 

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Brownbear where is the hookup on the 92's for the scan tool?
 

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