How to: The Comprehensive Brown Wire Mod Thread

[Sonic_Mikey]

Gonna beat a dead horse some more, but iv been looking over the wiring diagram in OnDemand and iv had a thought: Instead of doing all of this extra work with wiring and adding switches, could you not either space the front speed sensor out slightly, changing the frequency of the signal to the GEM (which should interpret this as slip/slower speed, engaging constant 4wd) OR snip the signal wire from the front speed sensor, splice it into the rear speed sensor with a resistor thus ensuring that no matter what the voltage being seen from the rear speed sensor, the GEM will always see slightly less front speed sensor voltage (slip) and allow 4WD?

I havnt been under my truck yet to confirm any of this but just from the diagram this system appears to operate much like this:

 

[03eddie]

I have an 03, 4.6. I’ve been thinking about doing the brown wire mod for quite some time now. Now that winter is approaching yet again, it’s on my mind. My question is will pulling the fuses under the hood for vbatt1 & vbatt2 do the trick? There is also a fuse in the cab under the dash that is in question. I’ve even read that 4x4 is lost when the harness is disconnected from the selector switch on the console/dash plate. TIA