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Brake lights on all the time

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Wana

Wana

Jedi Hopeful
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Greetings all. While walking around my '66 BJ8 this morning with the engine running, I noticed that the brake lights were on. They come on when I turn on the ignition and they stay on until I shut the engine off. I don't see how this could be related, but I did just finish installing a new fuel pump yesterday. Could I have hit/pulled some wiring while installing the fuel pump that would cause this? Would a bad brake light pressure switch cause the lights to stay on? Not sure where to go... any thoughts would be appreciated!

Wana
 
Just disconnect one wire from the brake pressure switch (either one, it doesn't matter). If the lights go out you have found the problem. If they do not go out check back here and you will get more suggestions and collective head scratching.
 
Hi Wana,



Just in case it turns out to be your pressure switch, which in my case was, (but the reverse since my brake lights would never go on!), I have applied an alternate solution to my BJ8 by installing a mechanical switch, leaving the existing pressure switch in place. In fact, nothing on my car was ever altered, with the help of some miscellaneous pieces from a Gilbert Construction Kit. See sketches and photos. Just offering as an alternate and again, if it is your pressure switch that's the cause (which by the way, I'm not sure if they can be purchased new, but I've learned they can be repaired).

Good Luck.

Paul
 

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As a footnote to this discussion, hydraulic brake light switches often fail when used with DOT-5 brake fluid. Some advocate the use of the Harley-Davidson hydraulic switch as a better, functionally equivalent switch for use with DOT-5. When I experienced this failure on my Mini I chose a path similar to what Paul suggested above. I added a mechanical switch to the pedal box and left the failed hydraulic switch in place.
 
Thanks guys! I'll try replacing the pressure switch first. But... (sheepish grin) exactly where is it?? I took a quick look and followed the brake lines but didn't see it? Of course, my wife would say the best place to hide something from me is right in front of my face...
 
it is under the generator. along the frame there is a fitting where a number of brake lines come together. it is screwed in that fitting. one with wires to it.

if you decide to stay with a pressure switch, i believe Russ Francis sells a heavy duty one that is supposed to last longer.

however, you can pull those wires and run them back in to the cabin. attach an electric switch to the bulkhead that would work off the brake pedal. i think they are more reliable. when mine goes, that is what i plan to do.
 
Thanks Dog! I'll pull a wire off as Jon suggested and go from there. I'll let you know...
 
Suggestion: disconnect both wires from the pressure switch and check across the switch for continuity. If so, it's stuck in the "on" position.

I like the simplicity of using the pedal switch instead of the pressure switch rather than in parallel with it.

The parallel switch system would only work as a backup if the pressure switch was stuck in the "off" position; if stuck "on", the lights would be on all the time whether one had a pedal switch or not.

Have been running a pedal operated switch since 2006. Several pix of the install starting here: https://www.pbase.com/stevegerow/image/70570841

BrakeSwitchesSchematic_Gerow.png
 
pkmh said:
... I have applied an alternate solution to my BJ8 by installing a mechanical switch, leaving the existing pressure switch in place. In fact, nothing on my car was ever altered, with the help of some miscellaneous pieces from a Gilbert Construction Kit. See sketches and photos. Just offering as an alternate and again, if it is your pressure switch that's the cause (which by the way, I'm not sure if they can be purchased new, but I've learned they can be repaired).

Good Luck.

Paul
Click to expand...

Nice drawings!
 
Ok, here's the latest. I went out to the garage. I turn on the ignition just to verify that the brake lights come on. Yep, they do. I turn off the ignition. I located the pressure switch. I unplugged one of the wires and turned on the ignition. No brake lights. I turn off the ignition. Just to verify, I plug the wire back on to the pressure switch and turn the ignition on. No brake lights! Huh? So I start the car and push on the brake pedal... the brake lights work as they are supposed to, with very light pedal pressure I might add. So, I guess for the time being my superior mechanical skills have taken care of this problem :wink-new:. I'll let you know how it goes...
 
Lucas just loves you---LOL
 
Wana - so you still have an irregular switch.

I see Moss (Brake Fittings page) has 3 different versions, the most expensive of which is $7.99. Might as well just replace it and maybe get a spare for when the new one gives out.
 
If you are going to stay with an hydraulic switch, give the switch that Ron Francis Wiring sells a try. More expensive but it also seems to be very sensitive to brake pedal pressure. Personally, like Steve Gerow, I have a mechanical switch in my car and have since 2008. I had the Ron Francis switch in my Jag.
Lin
 
Perhaps when I suggested pulling one wire off, I instead should have suggested tapping on the brake switch with a small to medium sized hammer. It is possible the diaphragm in the switch was just stuck in the on position and your tinkering with the wire freed it. It might have happened as you put your brakes on when you last drove it. It is possible just the vibration of driving might have also freed it. If this is possibly what the problem was my guess is you will see it again in the not too distant future. My anecdote is that there is a tractor on my farm that for months the crew has been saying the tachometer was inoperative. I finally got around to it and sure enough it was not working. 35 years of working on aircraft and my unconscious reaction was to thump the panel. Voila! Good as new, until it happens again. Enjoy your success. Consider yourself fortunate that the plastic part of the terminal on the switch didn't crack and break as you fiddled. I never assume the problem I start with will be the problem I finish with.:hammer:
 
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