I'm in the process of getting a 2001 F-150 Supercab that I recently acquired safe and road ready. After a month of repairing and upgrading some major stuff I'm down to some minor issues. On a first small test drive today I discovered thee were no brake lights. I know the bulbs are working because they work with the 4 way flashers. I considered several possible causes such as a fuse, a relay, a switch, a connector or a possible combination of any of those devices. I've eliminated fuses but since what is left of the owners manual is incomplete I don.t have any layout to show me what the function and location of the relays. I have also discovered the the pressure switch on the end of the MC is closed, ( same as on) which so far as I know is wrong. My reasoning says it ought to be an open circuit so long as brake pedal is not depressed. Conventional thinking leads me to0 believe the brake lights should be continuously on if that switch is closed but there are no lights on. I serched online for a PDF file of the owners manual and there are sites that say it is free to download the manual, however they require me to install an extension to my browser. I am reluctant to do this because the last time I did that it resulted in screwing up my browser which led to deleting my browser annd all of it's history. There are litterally thousands of all kinds of owners manuals that can be obtained online for free and no requirement to install any kind of extension. I need to avoid doing this if at all possible. So, if anybody knows where I can download this manual or has any good ideas how to fix this problem I would really appreciate your help.

 

Never mind guys, I finally figured the problems out. Now all I need is a spider monkey to get in there and get that switch changed out. Also, my son 600 miles away found a PDF of the manual.

 

Only difference is the Multifunction switch the power goes through for the stop and directional lamps.
If those lamps work on 4 way, it's not a fuse or those circuits after the Multifunction switch.
As for the master cylinder switch, if you have Cruise Control, that switch is closed all the time to provide power to the CC system.
When you step on the Brakes it goes open circuit to knock CC off. This switch has nothing to do with Brake lights like the old time systems did.
Also when Brakes are operated, part of the Brake switch apples an 'inhibit' signal to the CC circuit as a double CC knock off. It's required by Law so the CC does not keep driving the vehicle in cases of panic braking etc.
Good luck.

 

Thanks Bluegrass 7 for your reply... Since I posted this thread I did some more research and detective work. I did discover that the cruise control switch was closed. At the time I wasn't sure that was normal or if the switch was just stuck in the closed position. I suspected it might be OK and I noticed there was 12V on one side of the switch. That led me to believe the switch was intended to work as you described in your reply. Not having a complete owners manual or any shop manuals I had no certain comprehension of how things worked and that has been a real pain. I did manage to go on ebay and purchase a complete Ford shop manual and the electrical wiring diagrams manual. Of course it won't be here until Oct 28th when I'm all through getting things fixed and in order. As for the brake light problem I discovered that there was some problem either with the switch on the pedal or the connector for it. I managed to get my hand up in there and remove and put the connector back on. Somehow I managed to shake or move something and now the brake lights work. After my 74 years of life experiences I've learned to not be a trusting soul when it comes to electrical and mechanical things. I went online and spent the extra bucks for a real Motorcraft part . I have every reason to expect that problem to come back. I have yet to find an ambidextrous midget or a trained spider monkey to change the part. At my age and having had a stroke six years ago I don't think I'm capable of changing that brake switch because of it's location.
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