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#2401664 - 11/10/17 08:46 PM Is there a 2nd computer on a 91 Dakota?
poorboy Offline
master

Registered: 01/19/03
Posts: 5960
Loc: Freeport IL USA
OK, I pulled the dash out of a 91 Dakota to hijack the wiring harness. Over in the right upper kick panel is a black box about 5" square with a wire attachment of about 10 wires (I didn't count them). I know the mid 80s cars had a logic module in that kick panel, but I thought those went away with the OBD1 system. Is this box the equivalent to the logic module? My coupe has a dash wiring harness from a 90 Dakota in it and I don't remember there being such a box attached to that harness, but that was 5 years ago.

The OBD1 ECU was under the hood and the truck was a stripped down v6 5 speed with very few options. This box was pretty well hidden behind the heater/ac unit and I didn't even know it was there until I pulled the dash.

What am I seeing? Of course I don't have a picture of the box, but I suppose I can get one. Gene

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#2401672 - 11/10/17 08:55 PM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
buildanother Offline
I Live Here

Registered: 08/30/05
Posts: 10869
Loc: chicagoland,usa
I seen a box like that on one
of my 90 ramchargers. I thought it was a module for the rear wheel abs.

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#2401688 - 11/10/17 09:29 PM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
poorboy Offline
master

Registered: 01/19/03
Posts: 5960
Loc: Freeport IL USA
Well now, there may have been abs on this truck at one time. There wasn't anything there when I took it apart.
Would this be something I can remove? The "new" truck will definitely not have abs. Gene

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#2401720 - 11/10/17 10:36 PM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
rhad Offline
mopar

Registered: 08/19/03
Posts: 607
Loc: garnett kansas
if you are going to use the complete dash from the abs truck and not have abs the light on the dash will need to be removed,check close on the frame at the rear where the rear brake line is,if the modules are different use the non abs one
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#2401750 - 11/11/17 12:15 AM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
poorboy Offline
master

Registered: 01/19/03
Posts: 5960
Loc: Freeport IL USA
To make a long story short, I'm building a hot rod (39 Dodge pickup on a Dakota chassis, 5.9 Magnum powered), and the unhacked wiring from this 91 Dakota has volunteered as my wiring harness.

I will not be using the motor part of the harness, I'm installing a 5.9 Magnum with its attached trans and I have a Hot Wire stand alone harness to make it run.

The Hot Rod project is on the Dakota chassis, so I can use the Dakota harness to power everything other then the motor (like the lights, radio, gas gauge, wipers and so forth). I won't be using the Dakota instrument cluster other then the gas gauge, but I will be using all the switches from the dash, just not in it.

I probably should buy a fsm for the 91 Dakota, I have an 87 Dakota service manual, but its too old for the wiring, so the only thing a 91 fsm would be useful for would be the wiring diagrams. I can't seem to find just a wiring diagram for the Dakota anywhere. Gene

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#2402351 - 11/11/17 11:42 PM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
rhad Offline
mopar

Registered: 08/19/03
Posts: 607
Loc: garnett kansas
what year frame and rear axle are you using,my 92 has rear antilock and the module equalizer thing is different than a non antilock
it should look different,a quick look should tell the tale
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#2402885 - 11/12/17 11:40 PM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
poorboy Offline
master

Registered: 01/19/03
Posts: 5960
Loc: Freeport IL USA
I'm using the 91 Dakota frame. I'm using a 9 1/4 out of a 77 Dodge pickup, the Dakota original 7 1/4 is long gone because it was locked up and wouldn't roll. There was nothing on the frame at the rear indicating there was anything kind of equalizer there, and this was the 1st module I've ever seen, if that is what in deed it is. I have nothing to compare it with, and of course there isn't anything on the module telling what it is.

As I have read up on the anti lock setup, it appears the system was activated through the brake proportioning valve with an additional rear brake line, but there was nothing there either. Everything I've read says all Dakotas had this system, but other then the module under the dash, there is no signs of anything being on this truck. Guess someone went through a lot of work earlier in this trucks life. The odometer shows 198K miles, so who knows what has happened in all those miles. Gene

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#2403940 - 11/15/17 10:12 AM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
DaytonaTurbo Offline


Registered: 02/26/03
Posts: 20344
Loc: Manitoba, Canada
Not sure on what that would be. It would not be a logic module as you are correct in the ecu in the engine bay runs the engine/trans. It could be a body control module, I know the 90's cars ran them to control stuff like lighting, cruise, wipers, gauges. Or I guess it could be abs or air bag.

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#2404305 - 11/15/17 09:12 PM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
poorboy Offline
master

Registered: 01/19/03
Posts: 5960
Loc: Freeport IL USA
I took the covering off the dash wiring harness today because I need to shrink it down to fit in the 39 cab. I need to put 10 lbs of stuff into a 5 lbs size bag (or shrink down a 60" x 24" deep laid out wire harness to a 46" x 14" area). It appears the black box must be a body control module because there is at least 1 wire from each circuit (cruise, wipers, heat & turn) going to it. Guess I'm going to find out how things will function without it, I will try to unplug it to see what works and what wont. I'm at the point I might just wire the project myself from scratch. Gene

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#2406819 - 11/21/17 11:12 AM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
DaytonaTurbo Offline


Registered: 02/26/03
Posts: 20344
Loc: Manitoba, Canada
If it's anything like the mopar fwd cars, once they went to the body module, the switches all became low amperage signal switches with the body module having the heavy relays that turn on/off the lights, cruise, wipers, etc. On one project I changed the switches out from a 90's car to the older high amperage 80's switches and that worked fine because the body computer was still doing the heavy lifting. Going the other way wouldn't have.

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#2407120 - 11/21/17 09:04 PM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
poorboy Offline
master

Registered: 01/19/03
Posts: 5960
Loc: Freeport IL USA
Thanks guys. I'm on a mission to get this thing running and moveable under its own power. As is, I need to push it by hand in and out of the garage when I have a chance to work on it. Too soon we will be covered by snow and the push by hand will be done. If it doesn't move on its own, I will have to work on it outside in the weather, or more likely, I'll be done with it until spring.

The way its looking now, I'm probably not going to use much of the dash stuff. I'm not using the Dakota column because it has the clockspring in it and I don't want to deal with that. I'll be using an older 80s style column with the wipers and cruise on the stalk (the dimmer will be relocated to the floor). The 80s column I have is a better fit than the Dakota would have been in this cab. About the only stuff that looks like its staying are the lights (light switch looks like the older ones) and the wipers (adapted to the current column switch), because they are the intermittent style. The wiper system in this 39 Dodge cab is above the windshield, I'm not sure how this Dakota system will fit up there. That will be a project for another day.

Today I started the project of installing modern minivan bucket seats (not front seats) onto 80s style 6 way power seat brackets and into the 39 Dodge truck cab. Gene

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#2407252 - 11/22/17 07:20 AM Re: Is there a 2nd computer on a 91 Dakota? [Re: poorboy]
jerseybud Offline
mopar

Registered: 04/25/04
Posts: 610
Loc: Maine
That black box has to be the RWAL ABS module. Everything works when it is unplugged except the ABS. 91 dakotas did not have much for electronics- the glory years of simple trucks

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