brown wire mod on my truck

[jimbo74]

i have talked to several people around here lately, that have said that i can or cannot do the brown wire modification on my truck. there are words flying around like i have an awd, and otehr things that are confusing.

i wnat to know if i can do the brown wire mod on my truck. from everything i have found, i have a control trac 4wd bw4405 --- 3 position dash switch with 2wd, 4auto, 4lo

below are actual pics of my truck

there was talk about it being to disable the awd?

i saw the brown wire thread mod and it is jsut confusing me even more

there is 2wd, 4auto, 4lo -- that can be converted to 2, 4hi and 4lo? and i can have 2lo? what?!

 

[sparkyXplorer]

I thought that the brown wire mod was only for people with 4auto/4hi/4lo...but Don't quote me on that

 

[jimbo74]

I thought that the brown wire mod was only for people with 4auto/4hi/4lo...but Don't quote me on that

that is what i thought too, until today when others said different, and it wasn't jsut 1 person either, it was a couple, and they said they did it....

 

[dogfriend]

My recollection is that some of the early brown wire mods were done on the 95 -96 which have 2wd/4auto/4low so that you can get 2wd low range.

The brown wire mod prevents the transfer case clutch from engaging when the current is switched off (by disconnecting the brown wire). So it should work with your truck.

The part that is different compared to the 97 -01 trucks is they do not have a vacuum disconnect for the front diff. However, 2wd low should work the same.

The brown wire mod does not work on the 5.0L AWD trucks because the AWD system is mechanical only and is always engaged.

The 4.0L Control Trac 4WD is referred to as 4Auto in the service manual and the 5.0L 4WD is called AWD.

 

[FROADER]

Please don't bump your threads in the same day. It's against the Forum Rules...

 

[jimbo74]

colin, i had forgotten about that rule, and it was deleted almost right after it was posted



ok, so the brown wire mod i can do now... will it allow me to lock the 4x4 into 4hi instead of having it in 4auto?

 

[dogfriend]

ok, so the brown wire mod i can do now... will it allow me to lock the 4x4 into 4hi instead of having it in 4auto?

No. There was a lot of interest in doing that, but you would need to supply a PWM signal on the brown wire to get 4 high.

If you just supply a constant 12V, you risk burning out the coil that engages the clutch.

 

[jimbo74]

so all it will really do for me is give me 2lo?

if this is the case, i do not mind skipping this modification. this truck will mainly be my daily driver/family hualer

 

[dogfriend]

so all it will really do for me is give me 2lo?

Yep.

 

[SkanlaxJMO]

yes you can, if you want to test it, take out your driver seat pull up the carpet a little bit and snip the brown wire, then start it up put it in lo range and hit the gas it will spin the rears. or you can try turning it will not kick like in 4-lo.

 

[jimbo74]

yes you can, if you want to test it, take out your driver seat pull up the carpet a little bit and snip the brown wire, then start it up put it in lo range and hit the gas it will spin the rears. or you can try turning it will not kick like in 4-lo.

see, that wasnt my question, i am not doubting it can go into 2wd low, i wanted to do it to make it go into 4x4hi range instead of auto 4x4 and it appears this cant happen.

this is a mod i wont be doing, i dont need 2wd lo range

 

[SkanlaxJMO]

arg..your not getting it. They go hand in hand, you get 4-hi and 2-lo. If you are doubting the 4 hi send 12v down the TCC and stick it in 4-auto(on dirt not pavement) and you will see that it works. It will work on your truck, try it out it's really easy. It works with a 3 position switch one side is stock the middle(off) is 2-hi 2hi and 2 lo, the other side is 2-hi-4 hi-4lo.

 

[jimbo74]

arg..your not getting it. They go hand in hand, you get 4-hi and 2-lo. If you are doubting the 4 hi send 12v down the TCC and stick it in 4-auto(on dirt not pavement) and you will see that it works. It will work on your truck, try it out it's really easy. It works with a 3 position switch one side is stock the middle(off) is 2-hi 2hi and 2 lo, the other side is 2-hi-4 hi-4lo.

ok in that case that was what i was asking, however it was stated above that is is unsafe to dio this as it will burn up the coil, i dont need any coil burning up because i wnated to use 4hi instead of auto4x

 

[dogfriend]

A couple of years ago, I tested with a scan tool to see what the PWM signal duty cycle was in each mode. In 4 High, the duty cycle was 13.33%. That means the current was on 13.33% of the time, off the rest of the time.

I made an unwatchable video (I was holding my digi cam while driving on a muddy road) showing this.

http://homepage.mac.com/dogfriend/Explorer/iMovieTheater26.html

4 high is not the same as 4 auto. In 4 Auto, the duty cycle is only 0.78% unless the wheels start to slip, then it increases as needed.

 

[SkanlaxJMO]

if the coil burns up then why doesn't it burn up when it is in 4-lo for long periods of time?

 

[dogfriend]

In 4 Low, the duty cycle is 3.92% when stopped (I think this is to minimize binding when turning the wheels) and increases to 38.44% when in motion. So the current is on 38.44% of the time.

IDK, maybe you can get away with it. I haven't tested it. Maybe someone at Ford has? Maybe they limited the current for some other reason? IDK.

Personally I would error on the side of caution. But that's just my opinion.

 

[SkanlaxJMO]

idk..i did it it works for me, but i don't use hi for long periods of time, i just use 4 low...so idk

 

[dogfriend]

So how fast have you driven in 4 High with 12V on the coil? Does it bind in turns?

 

[gijoecam]

I've done the testing myself. It works. Could it burn up the coil? Possibly. However, there are more than a few members on here that have done it successfully and without an issue I've heard of.

Just because the TOD relay sends a PWM signal to the clutch doesn't mean that it cannot sustain a constant signal. I measured the current draw through the circuit using a Fluke 87 DMM placed in-line between the fuse and the T-case clutch coil, and it turned out the clutch only draws 4.7A. (It may have been 4.3, so don't quote me on that number... it was a while ago)

If it really bothered you, you could install a current-limiting resister in-line. I don't feel it's necessary, and here's why:

Regardless of what duty cycle the system is calling for, if the voltage measured in the brown wire is 12V, doesn't that mean the system is drawing the maximum current? If the clutch could carry more current than the system is providing, wouldn't the voltage drop off to some portion of that as well? (I'm no electronics expert... I had intro to electronics for mechanical engineers about 10 years ago...)

Either way, I've run mine like that without an issue (just for proof of concept). Until I hear evidence that it's harmful, I see no issue with recommending it. I'd still like to measure the current flow from the OEM system to compare it.

-Joe

 

[gijoecam]

Oh, and to answer Dogfriend's original question, yes, you can perform the brown wire mod. If wired up per the directions in the comprehensive brown wire mod thread, it will provide your vehicle (i.e. the 95/96 model years) with true 4high, as well as 2low in addition to the original 2high, 4auto, and 4low you currently have.

NOTE: in order to activate the 4high, you will need to flip the OEM switch to 4auto so that the GEM can lock the center-axle disconnect on the passenger side axle shaft.