I have a 1997 F-150 supercab Lariat 4.6L V8.

Last week I tried to shift out of park for about a half hour and the thing would not move. I looked at the reflection from my brake lights in a window and noticed that if I push my brake pedal down more than half way the lights go out. So I pushed lightly on the pedal and I was able to shift out of park. My brakes work great. I have newer Raybestos all around. I noticed my brake fluid was a little low so I topped it off. The truck stops solid when braking. Everything (mechanically) looks good, no leaks. Is there a sensor that monitors the amount of travel when you push down the brake pedal? This is weird to me. Any help is really appreciated. I do not want to get rear ended because my brake lights cut out after 1/2 pedal.

Thanks,

Rick

Clinton Township, MI.

 

This is not an expert opinion, but it could be in your switch on the brake pedal. Does your cruise control shut off when you hit the brakes? I haven't messed with any of these trucks yet to see if it is adjustable.

 

Thanks for replying Flatlander.

I am not sure, I have never used the cruise control. I did crawl up under the dash and looked at the brake pedal. It looks like there is some type of "sensor" on the stem of the pedal held in place by what looks like a black zip tie. Is this the sensor that you are referring to. I did try to see if there was any contact point or possible way to adjust it, but I did not see anything. I am not sure how it works. There are times when I am driving that my brake lights do work with the full range of the brake pedal but it is very inconsistent. I checked by the pedals to see if there were any loose wires or shorts but everything looks good. I am really stumped. All help is greatly appreciated!

Thanks,

Rick

Clinton Township, MI.

 

That is what you are looking for. The brake light switch is adjustable but i don't know the exact procedure for your truck. You would have to check a repair manual, probably the good one from the dealer, not a Haynes. You should get it fixed ASAP because it sends input to the brake lights, cruise control, ABS computer, and transmission so it can cause lots of trouble. If you go to a dealer they will probably charge an hours labor (about $65.00).

-Jon

 

Thanks for the info! I will have it looked at.


Rick

Clinton Township, MI.

 

DId you ever get that thing fixed? I just had to do a stop light adjustment on a Toyota. I imagine the procedure would be similar. First check your pedal freeplay by placing a ruler on the floor of the truck and seeing where the top of the pedal is alongside the ruler. Now push the pedal down with your hand until you feel resistance. You should start feeling resistance after about 1/2" if everything is good. If it is not you have some things that need to be adjusted that require tools that most people don't have so it is best to let the dealer adjust it.

If that checks out you need to loosen the locknut up on the stop light switch (looks like a grey cylinder with a wiring harness on the back. Depress the brake pedal 1/2" then thread the switch in until it makes contact with the pedal lever. Tighten your locknut and you good to go.

Like i said this is for a toyota but the procedure should be similar. I don't think the thing that is zip tied on is the switch. It should be boled on way up under the dash near where the pedal lever attaches to the booster.

-Jon

 

Thanks for the info! I am going to take a crack at it myself tomorrow. I do have pedal resistance after 1/2" and the brake lights work at 1/2". It is when I depress the pedal more than 1" when my brakelights cut out. You are also correct about the configuration of the sensor in my truck and from your description of the Toyota I think the procedure will work the same with my Ford. Anything else I should look for? Is it possible that the switch is shorted? It looks like the contact button on the sensor is spring loaded.

Rick

Clinton Township, MI.

 

Yep it is spring loaded, when the pedal is not being used the button is pressed and the lights are off. It is when you hit the pedal that the button releases and the lights go on. The switch must be bad instead of out of adjustment.

-Jon

 

Hey Ford4Ever I fixed it, but it was not the sensor!

I went to Napa and bought the exact same sensor (stamped "Ford" in the metal,, same part number stamped in it and everything) for $8.90 (It is manufactured by Dana). I got home with it and proceeded to disconnect the old sensor and brake pedal assembly when I discovered that the wire harness that connects to the sensor had "ripped" loose fron the wiring! I did a motion test (comparing how much the harness and wiring move when the pedal is depoyed to the maximum and discovered that the harness was cut way too short at the factory and whenever the pedal as pushed down to the max it pulled on the wires where the harness connects (which was wide open, by the way, and not taped at all!) So I extended the both wires about 2 1/2", spliced them in and taped them off. I then spliced in the harness end and taped it off (now I have an extra 2 1/2" of wire so that when the pedal is pressed down the wire has some slack so it doesn't pull loose from the harness!). I did use the new Napa sensor (which works perfectly by the way) and all is well. Took it on a long ride and everything is working great. Shifting is a little better too (not sure if it is related to the sensor problem).

Just wanted to let you know what happened. You may want to take a peek at yours and throw a little extra electrical tape on as a little preventative medicine. By the way, changing the sensor was a breeze. It took all of 5 minutes (took longer to extend the wires). Thanks again!

Rick

Clinton Township, MI.