Does the BWM (Brown Wire Mod) work for 4th gens?

[BrianDye]

Read damn near every page of the "3rd Gen BWM" thread, one person asked if it would work on a 4th gen, another member said no.

Saw at least two threads while searching that said the BWM DOES work on 4th gens.

Can anyone speak from experience? I would like the option to disable the automatic system, i'm not too fond of it after coming from an AWD vehicle, plus it would just be nice to have full control over the system. Mine seems to kick in when its not needed 99% of the time like turning onto the highway ramps, or something of that nature.

*EDIT: Scroll to the bottom, figured it out!

 

[MotorCityFats13]

even on the 2nd gens doing this mod causes the transfer case clutches to burn up.... and the 4th is way more expensive and complex... what are you trying to gain from doing this because fuel economy will only go up if you had locking hubs and with out some of the load getting shifted to the front you tend to break things inside the 5r55 and even 6r60's

 

[BrianDye]

It kicks in when its completely unnecessary, like hitting bumps which might cause one wheel to spin quicker or slower than another for a split second or when turning/merging onto the highway, plus the good stories ive read on here of members whose "ass" slid out around a turn, and then the auto 4x4 kicked on, pulling them straight off the road.

I dont get why the clutch would burn up? It just cuts the communication part that says "Hey, engage 4WD." I didn't know this was possible on second gens either, thought it was just 3rd and 4th gens.

My auto 4x4 kicks in when it doesn't need to, and stays engaged for a period of time, and i'm not fond of the noise it makes when engaged. I posted another thread regarding that issue, and I was told thats just how the system is.

 

[MotorCityFats13]

on 4th gens the fronts always get 20% power.... on my 98 I had 2 seconds before the fronts kicked in but on my 07 i cant kick it sideways to save my life.... but the open diff in the rear does not help anything

 

[BrianDye]

I've seen so many arguments back and fourth about how this system works, half say what you said, that the fronts are always getting a percentage of power, the other half say no power until wheel spin is detected.

I lean more towards the latter, and that's ONLY because the few occasions I have slid in the rain/snow we've had the past month, there was definitely a delay before the fronts kicked in and it was very noticeable when they did.

 

[MotorCityFats13]

i lean towards the side where I have had a 98 and a 07 on 4 jack stands and watched what they did... 98 would spin rears and fronts would lunge in very scary on stands... 07 all 4 wheels started to spin the second I let off the breaks also with the open rear diff.... ford never offered a limited slip because of the RSC.... I cant even slide it sideways unless i am on ice and this is only when I hold traction control button for 5 seconds to totally kill the system... this system really makes this truck no fun to drive but it turn way more safe

 

[BrianDye]

Reviving an old thread. Planning on some wheeling trips once I get my lift and tires installed. Really wanting the ability to disable the auto 4x4.

Im sure I could simply pull the fuse in the main fusebox under the hood labeled simply "4x4" but I would rather not have to pop the hood and such, as well as have my 4x4/wrench lights in the dash. (Read that in another forum)

Mine kicks in all the time getting on the highway, or any turns where I turn and get on the gas pretty good. One wheel probably barely breaks loose from loose gravel or dirt and then my 4x4 is engaged for the next (X) amount of minutes. Shouldn't need 4x4 where we're going to be wheeling, but I know it will constantly be kicking on from the auto which is why i'm really determined to disable it now, but from the convenience of a switch somewhere.

Pulled the 4x4 system wiring diagrams, some wire in here HAS to be the one, lol. On a mission to figure this out. Any suggestions/help welcome.

Sorry, had to split it in two pictures:

 

[MotorCityFats13]

when you put all 4 corners on stands you really get to see how the auto system works... it never really kicks on... its on 100% of the time splitting the power between front and rear... i hear its something like 80/20 and 60/40 when it slips but at the same time when its in auto you get 2 seconds to spin the rears to do a snow slide from a dead stop in a parking lot.... was the same on my 98 and 07 when I wanted to do a 180 degree spin in the snow.... but just because you dont need 4wd does not mean you will get any benefits from turning it off because it does not have locking hubs everything in the front still spins and gives drag

 

[BrianDye]

I wish I could record the difference when my auto kicks in. It's night and day, and it kicks in so often it's not funny

 

[BrianDye]

When my "auto" kicks on, its identical to me being in 4 high. It sounds like I swapped on a set of mild mud tires.

I can kick it back out of 4wd by hitting the 4 high button, and then press auto. The noise will stop, aka the 4wd stops. Whether its constantly sending power to the front wheels or not, is irrelevant in what i'm wanting to do. I want to disable it from automatically going in to 4wd when it feels necessary.

About to just do a trial and error on some of the wires in the diagram above on which one would disable the system.

 

[JeepGuy25]

I totally understand your frustration. I hate the auto 4x4 on mine. It kicks on, and you can 100% tell. Anyone that cant tell is oblivious. Usually if I lift off the gas for a second, and get back on it, its disengaged. Its just annoying.

And the bit about the hubs being locked all the time. This isnt a new method of 4wd. Ive owned tons of Jeep Cherokee's, and they have the same thing going on. Front driveshaft is always spinning. Disconnects in the transfer case. But you STILL get the benefit of never powering the front wheels. Just look at the full time vs part time Jeep transfer cases. The full time set ups are worse on gas. All other things equal.

The test of the truck being on the lift isnt a good one IMO. Of course 4x4 is going to engage. You are spinning the rear wheels, while the fronts are dangling. Its going to think the rears are slipping and engage the fronts right away. Now, if you could some how simulate rolling down the road, IE rotate the fronts at the same speed as the backs, and monitor the output of the transfercase, that would be a good test.

Brian here is a thread that shows which wire you have to disconnect to disable the 4x4. Its already been figured out and several guys have done it, with no reported ill effects yet. I plan to put it on a switch as soon as I can dig into it to see exactly what COULD burn up by doing this. Im not convinced anything can as long as you arent driving like a lunatic.

http://www.explorerforum.com/forums/showthread.php?t=364283&page=2

If you do it, post up and let us know how it works out for you. I plan to get a male and female matching plug for the 4x4 module, and creating a plug and play switch solution for mine. So I can just plug it back in if I need to sell the car or if it doesnt do what I want.

Justin

 

[BrianDye]

The test of the truck being on the lift isnt a good one IMO. Of course 4x4 is going to engage. You are spinning the rear wheels, while the fronts are dangling. Its going to think the rears are slipping and engage the fronts right away.

This ^^^^^^

I meant to address that suggestion when it was brought up, but completely forgot.

I can't see it burning anything out or having ANY ill effects though, as you're just disabling the system from being able to automatically kick in to 4x4. Im not disconnecting drive shafts, or something where the differential is still trying to send power or something along those lines. I don't plan on ever trying to do burnouts or anything like most of the people want to do with this mod. (I would **** bricks if this brick of a vehicle with this underpowered 4.0 could spin the tires)

My auto will stay on for usually a mile or more, depending on conditions outside. I have not tried letting off the gas, but pushing 4 high and then auto works for me. Ill have to try that.

Ill check that link out right now and see what they did.

 

[BrianDye]

This is also leading me to think alot of my problems are coming from my bad front end. I only have the "groans" and feeling in the steering wheel and such just like that guy in the thread mentions, and coincidentally I need an alignment, as well as ball joints and such. My left front tire is pretty worn on the inside too, so now im anxious to see how she sounds/feels in 4x4 when I get all these new parts on with my new wheels and tires.

 

[USMCBuckWild]

I did the mod in the thread above a year ago and have had no complaints. Hooked it to a little $0.13 toggle switch and no issues. Same as stated above as well, i did the male/femal connector so i can easily remove the entire switch if needed.

Super easy but besare there are 2 very similiar wires in the bundle.

My 4.6 does little posi burnouts (I had to test it!!) but is not thrashed or abused.

 

[BrianDye]

I bet that 4.6 is nice. I always say, if/when (knock on wood they dont!) my timing chain tensioners go, shes getting a 4.6 lol.

So im looking for the 4x4 module in the passenger footwell, and cutting the gray/orange wire?

Then just putting a switch in it? His thread confuses me a bit, he says just pull it out of the harness and ends the post.

 

[BrianDye]

Ok so in that diagram I posted above, it shows 2 harnesses going to the 4x4 module. Each one has a gray/orange wire. One harness its labeled Run/Start and the other is MTR CW.

Which one is it?


Im also concerned, these guys are all running V8's, aren't the V8's all AWD or was that just the second gens?

 

[BrianDye]

Here is the module, both harnesses have a gray wire with orange stripe.

One is a gray plug, the other is black.
The gray one is closes to the firewall, the black one is closer to the seat.

I pulled up the schematics for his 07 V8, the 4x4 is different. Same, but different. Im going to assume he means the gray orange wire in the harness that also has the green/red wire. He first mentions that he cut and switched both wires, which go to the same motor (Or whatever (M) stands for) hence the reason he got away with only switching one of the wires.

Ill post back results

 

[BrianDye]

So I cut the wire mentioned above.

The only difference is I don't have 4x4 low. The relay just clicks to try to engage but it doesn't engage. EVERYTHING else is the same. Auto kicks in, 4 high works, etc.

It's raining pretty hard, so I would easily get the rears to spin and not hear/feel the front end kick in but it does.

Wtf.

 

[BrianDye]

I just pulled fuses #23 and #26 under the hood (4x4, and 4x4 Module) and the results are what I am looking for. No 4x4, but the wrench light is on, and the 4x4 low button light is on as well. Plus I have to put both fuses back in or vice versa to achieve desired results.

So I pulled 3rd gen diagrams, and the "brown wire" is pin 17 on the harness I cut my gray/orange from. On the 3rd gen its labeled "DIFF LOCK SOL" and goes to the DIFF LOCK SOLENOID. On my 4th gen, its labeled "Clutch Coil" and goes to a magnetic clutch coil.

Wouldn't this be the same as the BWM on the 3rd gen? Im really wanting to get this done now that I have the harness all opened up and whatnot.

 

[JeepGuy25]

Yikes...dont cut the wires! De-pin them! That will avoid you having to splice a wire back together when it doesnt work.

I thought the thread linked was pretty specific for the wire, but I also thought that the 2006-2010's with AUTO were the same 4x4 module.

Try de-pinning the other grey/orange wire to see if that does it?

Unfortunately I havent started on mine yet, or really studied the wiring diagrams. I want to do it soon though. I have my glove box out right now for another install, so maybe ill go goof around with it. Although I have a V8, so I guess my experience is going to be different.

Let us know what you figure out. But def try to de-pin vs cut. Its way less permanent.

J.