I am not sure then where I should start then on getting this fixed. Should I splice a junkyard harness back in--would that even work? And if I could, how would I tell which wires to splice? Are they the same across all years?

Here are some more photos.


Behind the pedal ... nothing discernable. Reaching and feeling around, there's nothing there.





Wires coming in from the firewall. You may think that the ones hanging down have something to do with it, but they don't.
I've followed them out to the engine area a long time ago, they've been disconnected for years.





more wires ...



Hmmm ...

 

If you can find another 2001 at your local junk yard, then pull the brake switch and the wires as far backward as you can. Cut as much length as you can. That would be your ticket at this point.

 

A trailer!

 

Seeing that big blue wire marked ELECTRIC BRAKE, I'm thinking maybe somebody jury rigged an electric trailer brake system, and then yanked it all back out.

 

That light blue wire with the tag on it reading "Electric Brake" is for an optional factory/dealer installed trailer harness. That light blue wire is not your issue, atleast it shouldnt be. I have that same wire and it is not connected to anything, and my brake lights work properly. The missing wiring for the brake switch on the pedal is the issue, and its wiring. You say the brake lights DID work, so there must be a work around hidden somewhere that has yet to be found. I dont even see an old style brake switch on the pedal.

This is the circuit for the brake lights and missing switch.

 

This seems and sounds kind of hopeful, but I have no idea how to really read this diagram, though I am thankful for it. I'm still not sure what wires I am looking for. If I am understanding WT/TN and PK/DB correctly, this means the wires are White/Tan, Pink/DarkBlue? Is that what I should be looking for?

 

Yes, those are the wire colors for the switch. "F32" is the circuit (i dont even bother with circuit numbers as they change - i just look for the wires), and the number directly under it is the wire size. Where you see a black dot and "S302", for example, that is a splice where multiple wires are joined. When you see "C100" or whatever number it may be, that is a connector. I believe C100 and C200 are the two large white connectors in your pics with the gold bolts thru them. I dont know which connector is which tho without going thru the wires. the small numbers next to a wire at any given component is the cavity number in that connector for that wire. Wherever you see a "G304 or whatever number it may be, that is a chassis ground.

 

I'm thinking maybe that blackbox and aftermarket wiring mess in the picture above is a trailer e-brake controller? Do any of the wires through the firewall go to a switch or sensor tee'd off one of the brake lines near the master cylinder by chance? Some aftermarket e-brake setups use a pressure sensor in the existing hydraulic line to determine how hard to apply the trailer brakes, and sometimes they also use that to control the brake lights. If you still have the dash apart, do you see the white/tan-stripe wire going to the controller or the small black square relay. If you do, try unplugging the controller and the relay it and see if the brake lights go out.

 

Unfortunately, they are not, and there is no sensor along the brake lines that I can find. The black boxes are a Valet remote start something-or-other (dont have the remote for it, useless to me) and the other is some kind of alarm system. There are some white, blue, tan, and pink (with many other) wires coming from the Valet unit at different points. The alarm unit has white, blue, and tan wires among many other colors, and look a bit bigger. Haven't tried pulling any out, out of fear the alarm system could fry everything.

 

Maybe try having a look at your brake lines in the engine bay for anything with wires coming from it. Some older braking systems (not factory for XJ's) use a pressure switch which uses brake fluid pressure to activate the brake lights. If the system has been modified by someone in the past and you have absolutely no sign of a switch by the pedal, maybe this has been done.

 

Checked this out and can confirm there is NO pressure switch or senors along any of the brake lines anywhere along the vehicle.

 

A bit stuck on where to go from here. I am going to the junkyard tomorrow to see if I can find this harness I am apparently missing, after that, not sure. See about making splices? The alarm system I am not too sure about, and am afraid I might short a lot of other things by disconnecting it, unless someone's done that before with no problem.

 

Well, I'm not too sure what else I could suggest. When you get to the bottom of it let us know!

 

On that '01 its not an old school traditional brakelight switch. Its a small box with a plunger sticking out of it. It doesnt mount to the pedal itself, but snaps into a square hole in a bracket on the support.

As mentioned above, it very likely popped out of the bracket, this tends to happen if the plunger gets stuck.

 

Results from today's junkyard expedition. This is definitely nowhere to be seen in my Jeep, and the way the wires are together, there's no way it could have fallen behind anywhere.