In case you do choose this path, I'll save you the trouble searching.
Here's my post from March 2006 when a similar question came up:
Mind you, after wiring in the external PCM in 2004, I never had
another VR or alternator failure in that truck. I swapped engines in
2006, but left the old VR attached to the firewall for when I
eventually need it for the 94 engine :)
------------------------------------------
Okay, you forced me to finally dig out my old Outlook archives... my
VR mod pre-dates my Gmail account.
The instruction I was given on how to insert an older style VR in
place of the PCM VR was to wire the external VR in parallel with the
PCM. I didn't like the idea entirely. I kept the wire from the
alternator field output to the PCM input, but I snipped the PCM VR
output (the signal to the alternator - #14 wire on the 14-way PCM
connector). Then I just wired in the old style VR. Make sure it's
grounded! To prevent it from looking completely redneck, I bought a VR
harness (with the triangular plug) from NAPA for a few bucks. I did
this on my 89 Dakota... I imagine it's the same on 91-96 also, but
check your wiring diagrams for the PCM voltage regulator output. It's
really quite simple... and how much does a replacement PCM cost?
>From Sept. 2004 (basically what I just said... included for posterity I guess):
--- Okay, my fix worked. The truck is charging just like it should. Aaron mentioned wiring the voltage regulator in parallel with the PCM, but I was worried about the computer's incorrect output signal interfering with the replacement VR signal. Basically I wired it in parallel to begin with, except that before I finished, I clipped the #14 wire from the PCM 14-way connector (the PCM VR output). ---Don 89 Dakota Convertible 4x4 74 Dart Sport 340 ------------------------------------------
On 6/19/08, Don Rey <radon220@gmail.com> wrote: > I say skip the reman ECU question and splice in an old style external > voltage regulator. I did it on my 89, and I'll do it again on my 94 > ECU when it starts giving me problems. I can't remember the procedure > off hand, but if you search the archives, you'll find my post as well > as whoever I learned it from. It's pretty simple. > > The only things I've ever fried by overcharging (as a result of VR > malfunction) were the battery and alternator. Fried battery makes > sense... Fried alt becomes a question similar to that of the chicken > and the egg. > > Don in CT > 89/94 Dak Vert 318 NV3500 4x4 > 74 Dart Sport 340 >
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