RE: UPDATE to wiring diagrams as of 02/24/12

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THE WILD DOG
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2012/02/22 04:20:36 (permalink)

RE: UPDATE to wiring diagrams as of 02/24/12

 Ok I'm stumped.. I can't find any wiring diagrams for my alternator... If you may recall, I went to replace the battery in the new build and stumbled across several wires that were not factory. I have since been dealing with the mess by tracing everything out and can't seem to figure out how they re-wired this thing.  I've got the negative down so far but the positive is what is killing me. I can't for the life of me find any wiring diagrams that come close to my truck. 1995 GMC p3500 step van.   Any suggestions. my google-fu is turning up a goose egg. Autozone has wiring diagrams but not helping matters. Chevy dealership can only pull up a 97 but they say it could be different for a 95... How can they not pull up the right one ?   Here is my issue. From the back of the starter, they had a black cable going to the negative, ( reverse polarity ?? )  The reg ( positive cable was spliced with a copper split nut... and ran directly to the pos.  Now looking inside, the grounding cable should go like this, double black wire, grounded to the block, and the front chassis and lead to the negative. the positive wire should technically be coming from the solenoid and run from the back of the alternator to the solenoid  and from the solenoid, come directly to the positive term but it's NOT. ( this is according to the 97 wiring diagram)  in my case, again it's black to negative and red to positive ( both coming from the back of the alternator )  I'm hoping I didn't fry the alternator with the reverse polarity when I changed the battery and hooked up the wrong cables.    SMH... I've got 2 days to get this fixed and move the truck b/c the paint guy is coming from out of state to paint my truck.  Professional graphitti artist  is spraying the truck with spray paint. He does sick ass murals and he's doing both the whole truck and the other side of my trailer for $900 !!!    Now I have to find a way to clear coat it or seal it after he's done. apparently you can only clear coat paint when it's still wet.  WTF.
 






post edited by THE WILD DOG - 2012/02/24 16:45:35
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    edwmax
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    Re:wiring diagrams 2012/02/22 08:39:46 (permalink)
    THE WILD DOG

     Ok I'm stumped..        ..... I can't find any wiring diagrams for my alternator...... How can they not pull up the right one ?   Here is my issue. From the back of the starter, they had a black cable going to the negative, ( reverse polarity ?? )  The reg ( positive cable was spliced with a copper split nut... and ran directly to the pos.  Now looking inside, the grounding cable should go like this, double black wire, grounded to the block, and the front chassis and lead to the negative. the positive wire should technically be coming from the solenoid and run from the back of the alternator to the solenoid  and from the solenoid, come directly to the positive term but it's NOT. ( this is according to the 97 wiring diagram)  in my case, again it's black to negative and red to positive ( both coming from the back of the alternator )   .....

     
    I'm sure you can figure this out.    ... Apparently, there has been some customization of the wiring.  The 'split nut' splice is evidence of this.     .... This is just a mater of where the convince point for common connections & jumpers; ie ... at battery; back of Alternator; or some point on engine block (ground cable).  As long as the circuits complete, it is all the same.
     
    Question, where is the regulator?  ... in the Alternator???    Is this a diesel engine?   ... I think so, as I don't see a coil wire.   
     
    As a minimum to run the crank & run the engine:  
    • Alternator must be grounded:   by cable or engine ground.  You have direct cable ground with jumpers to the engine block.
    • Alternator positive to battery. for charging the battery.
    • Battery positive to starter solenoid (heavy cable).
    • A Hot wire (positive; 10ga or 12 ga) from battery to Ignition switch.
    • A hot wire from the crank terminal of the Ignition switch to the exciter terminal of the starter solenoid. This is to complete the battery connection (heavy cable) to the starter for cranking.
    • A hot wire (10ga or 12ga) from the 'run' or 'on' terminal of the Ignition switch to the regulator.
    • A hot wire (10ga or 12ga) from the regulator to the 'field coil' exciter connection of the alternator.   ... You indicated this wire is direct to the battery instead.  This can work, though.   ??? Is the regulator built into the alternator?  I think there would be more connections for 'regulated' voltage output and to prevent over charging of the battery, but I don't see them in the photos.     ..... If this wire is direct to the battery, then there must be a way to kill the engine; electric fuel pump or solenoid fuel switch wired to the Ignition switch run terminal.    ... If there is not a built-in regulator, then I think there may be a continuous drain on the battery when the engine is not running.  I'm not sure here, but it needs to be checked (someone's do-it-yourself wiring ???)
    I sure you already know all this.   .... Just look at the basics and fix the darn thing.
    #2
    THE WILD DOG
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    Re:wiring diagrams 2012/02/22 09:45:34 (permalink)
    Non deisel engine. I have to get under to see what's what. Driving me mad !!!!
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    edwmax
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    Re:wiring diagrams 2012/02/22 14:21:34 (permalink)
    This might help. Three basic wiring diag. of Alternators. Yours appear to be the bottom unit or similar.
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    THE WILD DOG
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    Re:wiring diagrams 2012/02/24 16:49:39 (permalink)
    ok, so it turns out that the alternator that I have currently is an industrial KING KONG & HULK version. It apparently doesn't get much more powerful than what I got.   It has no wire harness hook up on the casing, only the little wire you see coming out going straight to the battery.    So I gotta get it out of the truck and possibly rebuilt ( could cost up to $500 to rebuild )  If i choose to go with a new one, I would have to obtain the actual wiring diagram that shows which wires go into the wiring harness that plugs into the alternator ( which is the way it should be, however someone had to re-wire the system now to power the gauges from the current alternator )   I can NOT find anything to get me close to the color coded wires or find the actual wires that go into the harness. I've checked the starter and everywhere else, still nothing is visable.   BLECH !!!   and the paint guy is coming tomorrow to do up the truck.
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    marco226
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    Re:wiring diagrams 2012/02/25 07:08:21 (permalink)
    your driving youself nuts. just take it to a mechanic.
    make it his problem.
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    edwmax
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    Re:wiring diagrams 2012/02/25 10:13:00 (permalink)
    What is the model number of the alternator & manufacture's name?  It is on the tag on the back face (under the word 'what').    Can you crank and run the engine?  (you should be able to as wired now) If so test the max. voltage output at the positive battery terminal connection (red wire at the alt) with the engine @ high speed.    It the volts does not exceed 14v, then there is a working built-in regulator.
     
    There appears to be un-used terminal (screw stud on back). Check the voltage there to verify max. 14 volts.   This is the connection to wiring harness or power block for auxiliary equipment & light switch. Otherwise, connect to the battery terminal at the back of the Alt (regulated voltage); or at the positive battery post; or regulated voltage out terminal of an exterior voltage regulator.
     
     If you need wiring harness color codes, then you need the harness codes for that model truck, assuming the harness is original. This would be in dealer service manuals.  Good luck on finding one.
    #7
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