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Voltage output too high

tarbender's Avatar

Join Date: Feb 2004
Posts: 12

04-04-04, 09:47 AM   #1  
Voltage output too high

I have a 98 plymouth voyager,3.3L . First I thought I had a starter problem, with it just clicking a few times before starting. When I checked charging voltage with vehical at idle I was getting 18 volts. Not good. Possible voltage regulator inside Altenator or inside PCM? Any way of testing ?The manual says it's in the PCM and need to change entire PCM?

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Desi501's Avatar

Join Date: Oct 2003
Posts: 2,207

04-04-04, 03:05 PM   #2  
Re: Voltage output too high

Originally posted by tarbender
?The manual says it's in the PCM and need to change entire PCM?
That's a fact. There are ways to wire in an external regulator but I can't tell you how to wire it from memory. Maybe Mike from NJ will be able to help you with that.

mike from nj's Avatar
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04-06-04, 02:36 AM   #3  
mike from nj
on the back of the alternator there is one big fat wire(battery) and 2 little wires. one of the little wires (green with orange tracer) is 12 volts from a relay(that's not your problem), the other is the field control wire(it controls the charging rate) this wire goes directly to the pcm. if that wire is chafed anywhere and grounded, it will cause the alternator to overcharge(if it were unplugged, the alt would never charge). you need to ohm that wire from the alternator to the pcm, with both ends unplugged. if it has continuity to ground, that's your problem. if it has continuity, but not to ground, it's could be a pcm.

look for chafing near the dipstick tube, and possibly the top of the trans. look everywhere between the alt and pcm, but those places first.

then let us know what you find.

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