91 Plymouth Voyager has MAJOR electrical short

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  #1  
Old 06-12-11, 06:40 AM
rebel63's Avatar
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91 Plymouth Voyager has MAJOR electrical short

At least, it appears to be an electrical short. It will be driving along fine and then the battery light comes on and everything dies! It happened at night and the headlights went completely dim and all electrical components stopped working. Turn signals, emergency flashers, even the speedometer went to zero and the transmission downshifted to low gear at 45 mph! The engine kept running for about a minute after we stopped, and then it quit too.

After sitting a few mins, we tried to start it and the battery was dead, it only did the "clicking" thing. I turned the key to the "on" position and kept testing for turn signals or anything, but nothing worked correctly. After about half an hour, I turned the key back to the "on" position and the turn signals worked correctly, so I tried to start it and the battery was still too weak. We connected jumper cables from another vehicle and it started right back up.

We drove it for about five miles and the whole scenario repeated itself. This time it died faster because the battery did not have a chance to recharge, of course.

OK... we have looked things over and have NO IDEA what caused this. We looked for obvious wiring problems and never saw any smoke or telltale signs of the problem. Can anyone tell us where to even start with this one? I do not have a wiring schematic for this unit, but I'm proficient with electrical things and I just don't have a clue where to go after doing a visual inspection under the hood and what I can see of the interior harness.

All help will be greatly appreciated. Thanks!
 
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  #2  
Old 06-12-11, 10:14 AM
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You dont have a short. You have a charging system failure. Most likely alternator, but the voltage regulation for this vehicle is in the Engine Control Module so it could also be that. You should get the charging system diagnosed.
Hope this helps you,
Billy
 
  #3  
Old 06-13-11, 08:22 AM
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Thanks Billy.... like I said, it "appears" to be a short. I expected something like the charging system because of the lack of something obvious. This has to be something internal and I've never seen an alternator itself act like this, although it would not surprise me, but if the voltage regulation is in the engine control module, then THAT would surely act like this.

Does anyone have any ideas about bypassing this system with another alternator with a built-in regulator or SOMETHING?!!!! I wll not be going for a new ECM for this vehicle.... THANKS!
 
  #4  
Old 06-13-11, 09:16 AM
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First thing is to loosen clean and tighten ALL connections, incl all grounds to engine and body.
 
  #5  
Old 06-14-11, 04:38 AM
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I wouldnt recommend attempting to install something that isnt meant to be there. This could be a costly mistake as you might easily fry your ECM in the process. Then you are in a big pickle. New ECM, and whatever else... If you arent electrically diagnostic savy, I strongly recommend you take it to a reputable shop that can diagnose electrical systems. One thing to keep in mind, at night as you said is when this happened, you have the most draw on your electrical system. Ie. exterior lighting and whatever other accesories you have on at the time. The instrument cluster is also electrically controlled other than for illumination. The battery is designed to start the vehicle and then the chargind system takes over and maintains and the battery.
Hope this helps you,
Billy
 
  #6  
Old 06-14-11, 07:31 AM
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With 12 volt systems you either have opens or fires,not shorts. A visual check is not much help.Just like women you have to get involved to know what is going on. The first thing to do is charge and test the batt. Then check the batt voltage with the engine off then with it running to see if the charging system is working. The charging voltage should be 13.8 to 14.2 range. As mentioned before clean all connections. We always think of the hot side of a circuit but often forget the ground side which is just as important.
 
  #7  
Old 06-28-11, 06:13 PM
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I don't know if it is the same problem. But I had a 90 Voyager, and I would get the gen light, and lose all power if I happened to run through a puddle. When the belt happened to get wet, it would slip. It would dry out, after 5 minutes or so. But at night, with light, heater, whippers, and what not, it would kill the battery
 
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Old 06-29-11, 07:40 PM
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How old is the battery ?? Sounds like it's on it's way out ....
 
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