The great auto swap project

[Cabz]

Well I have done some figurin :brows: and I have pulled the secondary harness out of an XJ. I found out there are 3 harness sections under the hood on the XJ/MJ's the secondary harness has all the trans , tcu , ecu and FI conections on it.

So it looks like the swap will be a load easier, The only problem I have found is that the power/cpmfort switch is the only part of the auto trans wiring that is built into the interieor part of the harness.

 

it connects to the wiring that goes into the ECU about 6" from itI have found two of the wires from the switch on the dash that go to it .

So this may be a lot more doable than I thought.

 

To help the cause , can someone look at a wiring diagram and tell me where the three wires at the Power/comfort switch run to and where the three wires at the ECU conecttion come from ( the three wire plug is seperate from the two Main ecu plugs)

 

more hopefully to follow soon :D

[Cabz]

anybody :idea: :dunno:

[rejeep]

I could check my chiltons for you in the morning....

[comanchedude]

Cabz

 

Not sure I understand the question but My guess is your talking about the TCU "transmission control unit" if so the power comfort switch is wired from the C11 port on the TCU and also the power wire that runs from the fuse panel and feeds the neutral start switch

Or if you are doing your own wiring then you just need to run power fron the fuse box through the switch then to the C11 port

 

Now I don’t know what you have changed but I have converted a std shift Comanche to auto and all that was needed was the tranny wire harness and that is (stand alone harness) that can be pulled from donor and installed that simple "it is totally standalone" and the power comfort switch plug is already part of the dash harness and all that was required was the "switch"

Hope that helps some

[Cabz]

Cabz

 

Not sure I understand the question but My guess is your talking about the TCU "transmission control unit" if so the power comfort switch is wired from the C11 port on the TCU and also the power wire that runs from the fuse panel and feeds the neutral start switch

Or if you are doing your own wiring then you just need to run power fron the fuse box through the switch then to the C11 port

 

Now I don’t know what you have changed but I have converted a std shift Comanche to auto and all that was needed was the tranny wire harness and that is (stand alone harness) that can be pulled from donor and installed that simple "it is totally standalone" and the power comfort switch plug is already part of the dash harness and all that was required was the "switch"

Hope that helps some

 

What year was your MJ? the 88 I have and the parts donor have the same type harness that includes the TCU, ECU and all the FI connections all the way down to the O2 sensor

 

I pulled a trans harness from an 88XJ the trans harness was complete , but the power comfort switch was not wired to the TCU . two of the wires from the switch run through the int/dash harness down near the ECU harness to a three wire plug , What I need to know is what the other two wires are for ( the one extra at the switch and the one extra at the Plug just before the ECU)

[comanchedude]

I have a 1988 and 1989 Comanche

The tranny harness is not connected to the ignition harness and is completely stand alone on the 88 Comanche that I removed it from

I switched complete drive-trains to put the 4x4 on the better body “the 89”

All I know is that the tranny "TCU" and accompanying wire harness did not have any relationship to the "ECU" harness

Now I only change the wire harness that was under the hood for the engine controls and such. I did not change anything inside the cab (except installing the "stand-alone transmission TCU and harness) . The power comfort switch plug was ready for use in the 89 Comanche as part of the existing in -cab harness.

So if you just installed an AW4 into a Comanche that had a standard. All that was required for me was to remove the transmission, “TCU”-control box and harness from one truck and install on the other Also you will need to take the torque converter disconnect switch off the auto truck and install on the std truck

(Looks like a GM brake light switch and is up high on the brake pedal)

The plug for that was also part of the wire harness on the std shift truck

[Eagle]

Don't have one handy to check, but my recollection is that the comfort/power switch has a pilot light, correct? So it's an ON/OFF toggle switch, same as the factory fog light switch, and the third contact is the ground connection for the pilot light.

 

FWIW, Jeep did away with the switch in 1989 or 1990. Thereafter, all XJs (and MJs) came hard-wired in the POWER setting. Unless you are concerned about authenticity, I wouldn't worry about installing the switch.

[Cabz]

I have a 1988 and 1989 Comanche

The tranny harness is not connected to the ignition harness and is completely stand alone on the 88 Comanche that I removed it from

I switched complete drive-trains to put the 4x4 on the better body “the 89”

All I know is that the tranny "TCU" and accompanying wire harness did not have any relationship to the "ECU" harness

Now I only change the wire harness that was under the hood for the engine controls and such. I did not change anything inside the cab (except installing the "stand-alone transmission TCU and harness) . The power comfort switch plug was ready for use in the 89 Comanche as part of the existing in -cab harness.

So if you just installed an AW4 into a Comanche that had a standard. All that was required for me was to remove the transmission, “TCU”-control box and harness from one truck and install on the other Also you will need to take the torque converter disconnect switch off the auto truck and install on the std truck

(Looks like a GM brake light switch and is up high on the brake pedal)

The plug for that was also part of the wire harness on the std shift truck

 

That is very odd, I have an 88 std MJ I pulled the auto trans wiring from an 88 XJ and the tcu ecu and all the fuel injection is in One harness . It is Not a stand alone harness on mine, I have also checked several other MJ/XJ's and I have not yet seen a stand alone harness.

 

If you happen accross another one lemme know I will take a pick of the spaghetti harness I have it is about 1/3rd of the underhood wiring on the MJ

[Cabz]

Don't have one handy to check, but my recollection is that the comfort/power switch has a pilot light, correct? So it's an ON/OFF toggle switch, same as the factory fog light switch, and the third contact is the ground connection for the pilot light.

 

FWIW, Jeep did away with the switch in 1989 or 1990. Thereafter, all XJs (and MJs) came hard-wired in the POWER setting. Unless you are concerned about authenticity, I wouldn't worry about installing the switch.

 

Yup thats it on that end :D I need to get around to figureing out the other spare wire on the harness end near the ECU.

 

Everyone I know just runs the Power setting on thiers, Thats what I plan on I just do not know what the default is power or comfort.

[comanchedude]

That is very odd, I have an 88 std MJ I pulled the auto trans wiring from an 88 XJ and the tcu ecu and all the fuel injection is in One harness . It is Not a stand alone harness on mine, I have also checked several other MJ/XJ's and I have not yet seen a stand alone harness.

 

If you happen accross another one lemme know I will take a pick of the spaghetti harness I have it is about 1/3rd of the underhood wiring on the MJ

_________________

I was just trying to be helpful as I have done the swap on a couple rigs and they have been the same MJ (Renix)so I don’t know what else to tell you. (Maybe a XJ has the harness zip ties together?) But as you asked (If you happen across another one lemme know) you can look at My MJ anytime you like

I have explained in as much detail as I can and if you follow the harness were it comes from the TCU (that’s behind the passenger lower dash panel) you will see it goes through the firewall all by itself and has its own rubber grommet and at no point is it related to the engine control harness as that runs out the through a giant plug on the driver side firewall

Now I will say this based on a MJ

[Cabz]

That is very odd, I have an 88 std MJ I pulled the auto trans wiring from an 88 XJ and the tcu ecu and all the fuel injection is in One harness . It is Not a stand alone harness on mine, I have also checked several other MJ/XJ's and I have not yet seen a stand alone harness.

 

If you happen accross another one lemme know I will take a pick of the spaghetti harness I have it is about 1/3rd of the underhood wiring on the MJ

_________________

I was just trying to be helpful as I have done the swap on a couple rigs and they have been the same MJ (Renix)so I don’t know what else to tell you. (Maybe a XJ has the harness zip ties together?) But as you asked (If you happen across another one lemme know) you can look at My MJ anytime you like

I have explained in as much detail as I can and if you follow the harness were it comes from the TCU (that’s behind the passenger lower dash panel) you will see it goes through the firewall all by itself and has its own rubber grommet and at no point is it related to the engine control harness as that runs out the through a giant plug on the driver side firewall

Now I will say this based on a MJ

 

I do apreciate your help on this , I am not trying to argue at all,

One of the things I think we are getting crossed up on is the drivers side main plug near the Brake booster.

That is not the plug I am reffering too.

 

I pulled the interior panel and found the TCU I then pulled the gromet out of the firewall and pulled the TCU plug out to the engine bay.

the wiring for the TCU goes into a larger harness , that harness has several plugs on the relay side of the engine bay that include the relay plugs coil leads. this end of the wiring also has the trans plugs for the auto trans.

If you follow the harness the other way it splits into several parts , One part goes through another gromet and straight to the ECU. The other section goes to the C101 conector just above the brake booster that plug feeds all the injectors and engine sensors.

 

That is what I have yours might or might not have the C101 conector which may be the diffrence in our wiring.

 

All I need to know is where few wires run to and I'm set , I need to know how to setup or wire the power/comfort switch to the power mode .

 

the wiring for that switch on the auto XJ runs seperatly through the inteirior harness

 

Thanks for your help

[87manche]

Cabz,

I've got a few quesions for you as I'm getting an AW4 242 combo to put in the MJ.

Trans crossmember the same? Does it have to be moved?

I realize the trans mount will be different.

Pilot bushing bearing? Does the auto have one or does the snub snout on the TC just plug into the crank. The trans combo is from a renix era Jeep, 88 or 89, so it has the proper flex pate and all.

I will be getting the "TV" cable that goes to the throttle body and the shifter/bezel. I will not be dong the TCU, my AW4 is going to be completely manually contolled. I'm lazy and hate wiring harnesses, and I'm an electronics dork that wants paddle shifters.

Does the AW4 have a wiring pigtail on it, or does it have a plug in the side? If it's got a pigtail I'm all set, I can just graft into it, if it's just a plug I would appreciate some info on it, so I can source a male one to build my custom harness into.

Pictures would be great!!

Thanks.

[Cabz]

Cabz,

I've got a few quesions for you as I'm getting an AW4 242 combo to put in the MJ.

Trans crossmember the same? Does it have to be moved?

I realize the trans mount will be different.

Pilot bushing bearing? Does the auto have one or does the snub snout on the TC just plug into the crank. The trans combo is from a renix era Jeep, 88 or 89, so it has the proper flex pate and all.

I will be getting the "TV" cable that goes to the throttle body and the shifter/bezel. I will not be dong the TCU, my AW4 is going to be completely manually contolled. I'm lazy and hate wiring harnesses, and I'm an electronics dork that wants paddle shifters.

Does the AW4 have a wiring pigtail on it, or does it have a plug in the side? If it's got a pigtail I'm all set, I can just graft into it, if it's just a plug I would appreciate some info on it, so I can source a male one to build my custom harness into.

Pictures would be great!!

Thanks.

 

The crossmember looks the same to me , The Uniframe seems to have a spot where you can move the Cmember back some

 

The auto does not use a piolt bearing , just pull your old one and you should be set. The converter has a snub tip on it that sits in the crank end

 

The AW4 has a three plugs/ setup that will run up to the back of the engine area on the pass side , I think the plugs are a 6 wire, a 7 wire and a single wire three plugs in all so you should be able to reach it easy enough

 

don't forget to get the tcase shifter ( or the rods ) from your donor , I know they are diffrent from the Ba10 to ax15 swap.

I just can't remeber if it is just the link rods or the whole shifter.

 

Lemme know how it turns out

[87manche]

I've not got a whole donor jeep, so I may have to source one locally. I've got an AX-15, hopefully they're close enough to make it work. If not, I'll set the selector to 2WD until I get the right linkage.

So, just to clarify, you swapped an auto into a std truck and did not move the x-member?

[Cabz]

I've not got a whole donor jeep, so I may have to source one locally. I've got an AX-15, hopefully they're close enough to make it work. If not, I'll set the selector to 2WD until I get the right linkage.

So, just to clarify, you swapped an auto into a std truck and did not move the x-member?

 

Nope I havent done mine yet :cry: But there are two mounting positions you can choose from .

The Ba10 xmemeber mounts to the farthest forward holes and the aw4 should mount to the back set, moving the xmemeber

[87manche]

ok, well, I've got an AX-15. and I know that the AW4 is a similar length. My X-member is already at the aft set of holes.