UPDATE ON ISSUE - had to go save wife yesterday she blew a brake line , on way home she said her bronco had no brake lights so after I fixed the blown brake lines I started looking into the brake light problem , fuse was blown so I put another one in and it blew instantly so I unplugged brake light switch still blows fuse so I pulled the haz relay cans still blows the fuse then I pulled off the multifunction switch and unplugged it still blows the fuse then I grab my meter the red wire with white tracer on fuse and haz relays have continuity to ground and the green wire off brake light switch is also touching ground , does anyone have the schematic for this truck I cant seem to find it online and my buddy at ford is off this week I found a few that were close but some of the colors don't match , or has anyone had this problem? I hate to pull the dash if this wire is connected to something else since the wire changes color from fuse panel to brake switch , thanks in advance

 

ok I traced it to the brake pressure switch/ cruise control switch on master cyl. if I leave it unplugged it does not blow the fuse but now it shifts like a drag car , anyone know where the other wire from brake press switch go to? one comes from #13 15 amp fuse but cant find wiring schematic to trace other wire I assume it goes to pcm or trans due to the hard shifts now . thanks for any info on this

 

Check back late tonight or tomorrow morning, I have some info from 1994 EVTM, but time is tight right now.

 

Ok sounds good thanks . Wife will be happy if I get it done soon and so will I so she stops driving my f350 lol

 

Your Bronco being a 1996 means it is OBD-II, so will have a EEC-V PCM rather than EEC-IV like mine. So there will be differences in engine controls and oxygen sensors, plus yours is probably mass air flow metering, rather than Speed-Density like my 1994. That said, this is what the 1994 EVTM shows for distribution from instrument fuse panel fuse #13, 15 amp:

From the fuse, a R/W wire runs to splice S236. From there it branches off in three directions:
To the brake pressure switch on the master cylinder, color LG/R;
To the Brake On/Off Switch (BOO Switch) at the brake pedal, color LG/R;
To the Hazard Flasher, color R/W.

Now, following down each of those three branches one at a time:

After (the other side) the brake pressure switch, a BK/Y wire runs to the Speed Control Servo/Amplifier module, where it powers/removes power from the servo clutch.

After (the other side) the BOO Switch:
A LG wire runs to splice S240, a LG wire continues on to the clutch pedal position switch (or a jumper there if auto trans), then via a T/LB wire to pin 7 of the Speed Control Servo/Amplifier Module.
Also from S240, a LG wire to pin 2 of the PCM, letting the PCM know if the brake pedal is pressed or not.
Also an LG wire to pin 35 of the 4WABS module, to tell the ABS controller that the brake is pressed.
Also from S240, a LG wire to the electronic trailer brake controller (optional) plug.
Also from S240, A LG wire to the Shift Lock Actuator in the column.
Also from S240, a DG wire to the high-mounted stop lamp.
Also from S240. a LG wire to the hazard switch.
Actually it looks like the PCM and the 4WABS module get there BOO Switched wire via a splice S121 that is downstream from S240 down one of the LG wires. They change from page to page on some.

I didn't run down through the hazard switch.

Your Bronco HAS been taken in for the recall fix with the pressure switch, right? That unplugged the plug from the brake pressure switch on the master cylinder, and inserted in series a recall-supplied small harness that has a 2 Amp in-line fuse wrapped up in it. So if the diaphragm on the pressure switch leaks internally and creates a short to ground, the 2 Amp fuse is supposed to blow, rather than brake fluid conducting and starting a nice electrical/chemical fire that consumes the vehicle.

 

Yes I had the recall done it started on fire but I caught it in time it was right after I bought it and didn't receive recall yet . I traced short up to the brake press switch I swapped out a new switch and it still blows fuse when plugged in so now I left it unplugged and it doesn't blow the fuse but it shifts hard like a shift kit is in it so now I have to chase the wire back into the truck . So everything from brake lights up to fuse panel and up to switch is good I'll have to check wire colors up to switch I think its either red/w or green/y or w if I remember correctly . I'm looking for a schematic from switch to maybe pcm, trans or anti lock brake mod I think or like you said speed sensor . Both my ford techs are on vacation out of town or I would have them print it up for me with a flow chart . I'll check in morning for correct colors I'm tracing your post sounds like same colors I've been chasing . Thanks again

 

Oh damn I read that wrong you already posted after switch lol sorry I'll check that in morn and see what I find

 

waiting for the rain to quit its been pouring on and off today may have to wait till tomorrow

 

Ok at the pressure switch on master I have lg/r and a bk/lg wire the black with light green shows continuity to ground and when I plug it in it blows the #13 15amp fuse . Looking for schematic for the black/light green wire now .

 

Ok found the plug at cruise control unit with 2 burnt up terminals 1 I'd Blk/lg and the other is pink and light blue it looks like . Going on test run to see if it shifts ok when unplugged

 

Nope still won't shift right guess I'll be ordering a cruise control servo or what ever it is and have to find a pigtail

 

If there was a failure in the servo assembly, unplugging the servo should remove the load from the wire delivering power to the servo's clutch circuit via the brake pressure switch.

Unless the cooking of that harness-end has allowed the power feed wire to come in contact with another circuit in the plug.
One thing you could try is to snip that wire from the pressure switch to the servo plug, right near the servo plug, but far enough back into the harness where the wire insulation is still good. Tape the harness-end of the cut wire, and take it for a drive.

 

Yeah guess I can and see what happens but it smells like burnt electrical so prob going to order new pigtail and module anyways and hope the problem ends there . Will be back with update soon

 

Sorry been busy . I got it fixed I bought pigtail and cruise control module . Brake lights work and it shifts fine again . Thanks for the info

 

That's great!

Thanks for posting back with the resolution.