How to: 4WD conversion for AWD and possibly 2WD

[Duranged84]

I have completed my 4WD swap on my 03 Mounty, here is some info, tips, and how to pull it off---- Mine is a 4.0, don't know if theres any relevant differences for the V8.

Now, the Mountaineer was originally AWD, but was missing everything for the system except the transfer case, Which, as you all know is a purely mechanical system, which is why I'm almost sure this will work for 2WD trucks as well. I need someone to post up a clear picture of their underhood fuse block, and to see if you have the 2 VBATT fuses with power to them, or at least the posts for both sides of those 2 fuses, then test them for me to see if they have power. My donor truck was a t-boned 03 Explorer XLS, I know a lot of wiring is different in 02, and read somewhere that the 4x4 control module was integrated into the ECM in 04-05. If someone has more info on that, I thank you in advance. I recommend looking for your wiring and electronics from the same year truck as yours. This does not include adding or any promise of retaining Advance Trac if so equiped. Only the factory Control Trac auto 4wd system.

---What you need---
Complete dash harness from your donor, must match your current trucks options as far as manual or digital HVAC controls, and with or without message center. Thats it. If someone could check on the heated seats option as I believe its part of the console harness that comes from the dash, Mine does not have them. Im thinking that may be what the other blank plug is for under the console. The plug for the backup sensors is also there on both harnesses whether its installed or not. There is also another square plug on the radio harness on both with only a couple wires which I *think* is for the steering wheel controls, somebody confirm this?

The 4x4 Control module, and its harness that goes from the TC motor up through the floor to the module and one plug to the dash. Lastly, the selector switch that goes in the dash bezel.

If your coming from 2wd, You'll need the front differential with mounting bolts, cv half shafts, front driveshaft, transfer case(Probably transmission too, although I've read the 2wd rear housing section is the same length as the transfer case, I dont know if the output shaft is the same so if anybody can confirm, I will update the post)

**Directions assume you have a donor truck, so if you were lucky(or unlucky) and got the parts already pulled, I'm sure you can figure out the directions. This also assumes you already have AWD or can install the front differential, transfer case, etc. If you are AWD, swap the transfer case for the Control Trac transfer case**

Disconnect battery, wait however long if you're worried about working near air bags----

To begin, Remove entire Dash assembly from both trucks. I have a write up for that if you want to look through it, very(maybe overly) detailed.

http://www.explorerforum.com/forums/showthread.php?t=403359

I left my drivers seat in this time, but passenger seat and console have to come out. Pull the carpet back on the passenger side and you'll see a wire harness going through the floor board, near where the back of the front seat was, and a rubber plug blank, pop that blank out. While you have the dash out, you can go ahead and repair that broken recirculation door and any other broken doors/actuators.

Also detailed in this thread by user Curtis http://www.explorerforum.com/forums/showthread.php?t=284042&highlight=fresh+air+door and EyeintheSky57 here http://www.explorerforum.com/forums/showthread.php?t=316624&highlight=fresh+air+door
I was able to remove 2 of the nuts on the engine side of the firewall for the HVAC box and pull it out far enough to get the 2 screws on the firewall side of the recirculation housing.

You can use the entire dash if you choose to, Just keep your gauge cluster so miles are correct, or look at the Mountaineer cluster swap thread if you're using a different cluster. I swapped from tan to grey interior when I bought the Mounty, and my new donor truck was tan so I chose to swap the wiring harness.
Mountaineer Cluster thread by XtremeRanger --- http://www.explorerforum.com/forums/showthread.php?t=218636

Take the dash assemblies somewhere with plenty of room to work and move them around, blankets or soft carpet or even a couch are good places to work on it. I would start with the dash that will be going back into the truck. Take pictures(I didnt take many sorry) So if you forget how something is routed you can go back and look. It really all lays in place pretty good though. Carefully free the wire harness from any connections, screws, brackets, and pull the screws for the fuse box, and bulkhead connector on the passenger side. Once you fish it all out lay it out where its not a bundled mess. Repeat for the donor dash/wiring


While they are both out (dont confuse them) check each plug to ensure every plug is there, has the correct amount of wires, and correct colors in each position. VERY time consuming, but you don't want to get everything swapped and back into the truck and find out somethings not right or the build date was too far off and one wire changed. My original harness had a plug where the 4wd selector switch wire is (I dont have message center) and I believe it is for the message center buttons? My 4WD harness did not have this plug, only the 4wd selector switch plug. You will also find a new green plug that goes to the right of the glove box, in the same location as the plug for the HVAC and vacuum line junction. Thats where your 4x4 module harness plugs into the rest of the dash.

The Green arrow shows the console/airbag module harness section, The red is the 4X4 module, and the Orange is the 4WD harness section. **Photobucket didnt save my arrows, The center most harness pointing down is the console/airbag module, The far right harness goes from the TC motor to the Module and you can see the green plug. ***Edit, it seems photobucket got my arrowed picture fixed but I'll leave the explanation in case it ever screws up again. ***

Hopefully when you removed the 4x4 module, You removed the one vertical bolt which allowed the bracket to come with the module, and will make install a breeze, slide it onto the blower housing and put that screw back in. Put your dash back in and take your time routing the shifter cable back where it should go and making sure everything gets hooked back up.

Now, (and you can do this when changing the transfer case, I put this engine and transmission/transfer case in 5k miles ago) Crawl underneath with your TC to 4x4 module harness. It has to go in from the bottom unless you want to drop the gas tank. The plug on the TC motor side is too fat to fit between the floorboard and the gas tank to get where it needs to go through the floor. Feed one plug through at a time and hopefully have a helper up top to pull them through and keep them from falling back in the way of the next plug. Once all three plugs are inside, feed the rest up to the rubber plug and stick it through. Secure the harness with its retainers or zip-ties if any retainers broke. I found several places to zip-tie mine up well away from the driveshaft flange.

Back up top, route the wire harness over to the side where the other harness runs under the kickplate. The black plastic channel pops open from the outside edge, then just run it along that and up behind the 3 grounds that bolt to the passenger kick area. You should have a couple retainers and they should line up to where they can clip into. Plug in the 2 plugs on the control module and the green plug to the dash harness. Double check that everythings hooked back up, and your steering shaft is bolted back together, hook your battery back up. Start the truck and watch the 4WD HIGH and 4WD LOW lights come on, hit the button to check 4high, put it in neutral and hit 4 low and feel/hear it lock into 4 LOW, go back to AUTO, put it in park, get out and do a dance that'll make your neighbors question your sanity.

When you get done acting like a kid, finish putting your truck back together and go play!

You will need to do an idle relearn procedure also, So hopefully your truck was completely cooled off when you hook the battery back up, or do it after its sat and cooled completely off. Unhook the battery, (if your truck was all the way cold when you hooked it up after the conversion, do this before playing with your 4WD, or anything.) Hook battery up, start truck, and let idle for 10 minutes without touching anything, no throttle, no ac/defrost, nothing. If theres more or I missed a step someone knows about, feel free to add in comments and I'll update.

Mud pics to come after I replace a u-joint in the front drive shaft.

:exp:

Some minor side notes----
As stated, my donor was an XLS, no option truck, I had the ECM, Security module, Key and switch but did not need them. My original AWD ECM recognizes or doesnt care about the 4WD system but it all works properly.
Also, even with the dash harness being from the no option XLS, all of my luxury stuff works and had the plugs there, were wired correctly. My Mountaineer has the following things that the XLS did not ---
Auto dimming mirror, lighted/heated rear view mirrors, adjustable pedals, rear HVAC, Auto head lights, foglights, power seats, compass/temp on gauge cluster, lighted visors, keyless keypad on door. All of my options are fully functional.

I originally planned to use the donor ecm/security module to ensure the system would all play together properly, with my research, It appeared I would have to have it programmed to get most of my features activated and functioning and, I forgot to pull the door lock cylinder from the smashed door before I junked the truck, Which means I would have had 2 keys to the truck and would set the alarm off any time I needed to unlock with the key. More headache and more money. Thats why I decided to give it a shot with the original ecm and security module. So for sure in my case, 03 to 03 same engine/trans, I was able to use my original ecm and security module with no issue. Also since I already had the Mounty gauges, I didnt have to worry about the mileage changing. Now, I've only seen one other person get their hands on Mounty gauges with the correct 4wd lights, So I cannot say for sure that you'll get them. If anybody else has any info about that, I'd love to hear it so I can add to this thread where exactly everyone can find them, since there wasn't a 4WD 02-10 Mountaineer made.

Also, to ensure that everything plays together nicely, get your parts from the same vehicle if at all possible. There are several posts where people have mismatched their 4WD module when replacing it and having a different number on it than the original causing problems, not working, or popping fuses, etc. I did NOT pull my ECM to check the codes on its sticker, so I dont know if that could be a factor and I lucked out with a matching ecm. I do know the 4X4 lights never lit up during the gauge test when starting (or any other time) before adding the module.

Also looking at part numbers, the dash harnesses option wise should be as follows-- Match to your equipped options from your donor --- With or without message center, manual or digital hvac controls, and with or without audiophile sound system

I know my dash and harness before this swap, I put in from my 2wd explorer, and had no issues with the ECM or anything else, and the part numbers show the same for 1 speed(AWD) transfer case and 2wd equipped trucks, so pending what we find out about the ABS, Im still thinking more that this swap will be as easy into a 2wd (plus adding the front drive components, which will all bolt up).


Also, if anybody has info on the ABS pump differences, I noticed the AWD and 4WD use one ABS module, and the 2WD was a different part number. Anybody that can add some of these missing bits of info I would appreciate it.

And for those that always tell people to sell their current truck and buy the one with the options they want--- After selling off what I didnt use or need, This swap cost me my labor. I think I actually came out with a profit by the time everything was done. If you want to do something to your trucks, dont let people talk you out of it too easily. Most anything can be done reasonably if you do your research and do it yourselves or get some help.

 

[wem390]

Excellent work! Props to you.... I have a 2002 Mounty AWD with the 4.6, not sure if can get a donor like you did and I definitely do not have the space for one, I am thinking of just wiring up the transfer case myself. The transfer case you can get for cheap used off ebay. If I hard wire it, I would loose the 4x4 auto function - it would be just a 2x - hit the power and go to 4x4 with full power to the back and front. Which is fine (I live in SoCal). Engaging the low drive would be easy as well, but I would not have the protections the 4x4 module gives. However, with your work, I need to reconsider everything. Thanks for the post!!!

 

[Duranged84]

I honestly think the module, dash harness, and transfer case motor is all the same between 6 and 8 cylinder models. I will look through wiring diagrams again but dont remember seeing anything that was noted V6 or V8 only. SO, with that said, try to get the parts from the same vehicle and that the vehicle is the same year as yours. Interchange shows the actual transfer case to interchange between 02-04 at least. Check Car-part to locate parts local to you. When you get the dash harness(and module, harness to tc motor, and tc case motor) make sure the donor truck has the same basic things as yours, with or without message center, manual or digital hvac, and regular or audiophile sound system. The rest of the options should all be wired in with plugs available. If you go through with it, post up and let us know how it went, and new information you can add would be welcome too.

The auto function is very nice if you drive as spirited as i tend to.... And when you need to get out of the way of idiot kids with their parents car/truck.... It just grabs and goes. It definately is worth the upgrade from even a functioning awd system to me, especially as grumpy as our AWD systems are... I read somewhere that the transfer case motor as a pita to just hard wire as it wasnt that simple. Thats what prompted me to take on this project, I originally wanted to just wire a switch to it and run it like that. May be a way to do it may not. If you do look farther into that, post up what you find. Im sure the wiring part and dash removal scares some people and would give them an easier option. I am very pleased with the factory A4WD though.