74-75 stoplight switch

According to the archives, there has been some discussion of this in the past, but I never found a resolution....

Does anybody know how the pedal-mounted stoplight (brake) switch works? Best I can tell, it was only used in some 74 and 75 models.

Here is a picture.



It mounts on a pin on pedal, and apparently rotates slightly when the pedal is pushed, enough to activate the switch. However, I cannot figure out what it is rotating with respect to, except the tension of the wires connected to it.

Mine is starting to become erratic, and sometimes will work with slight pedal pressure, then go off under full pressure.

I'm considering replacing it with a pressure-style switch. Does anybody have any suggestions? Are they just standard 1/8 NPT?

Thanks.

 

it is my understanding that it mounts on the same pin as the m/cyl push rod
as the pedal is depressed, resistance/pressure in the m/cyl causes the push rod to stop, yet the pedal movement continues slightly.
as the head of the push rod pushes on the switch, the contacts open/close when the switch comes into contact with the head of the push rod. It is true that the switch seems to "float" and can move/turn on the pin.
been a long time, and I don't own a 74/75 model CJ.
later models just used a spring loaded stationary mounted switch, activated when the pedal moves away from the switch

 

If i recall correctly the xjs use a similar switch but I do not recall if it is the right diameter. Recently I changed mine to accomodate a booster and changed it to the fsj style. What was interesting was that the pedal hanger was setup for this other style of switch and I did not have to drill any holes.

Karl

 

I have a 73 and that part does not hold up to rain. I've had to replace it twice

 

Jim is correct in his description of how it works. I had the switch off of the '74 I was just working on. It was being erratic like you describe. My problem was that I'd painted everything and it wasn't getting a good ground. Little sanding here and there, a little oil, and it worked like new.

I think I'd replace the stock unit before going through the hassle of tapping into your brake lines to install the pressure switch. Much more time consuming considering the need to re-flare the ends, install the switch, then bleed the whole system....

Just my .02

 

My 73 has that same switch. Mine was not working unless i pushed the pedal hard. I replaced it in February and have no troubles yet. I'd try replacing it, mine had worn out on causing it to be sticky, yours might be worn too.

 

I just replace mine on my 75. It only worked once in a while. no problems since the change.

 

Ok, I think I got it. Now that I've looked at it closely, I more clearly understand Jim's description. It still seems a little odd to me to design a switch that depends on the play between the pedal and connecting rod. The switch was in fine shape, but the cotter pin on the end of the post was missing, and things had worked their way loose. Thanks for all the help.

 

The switch is in the OPEN position when the pedal is up. When you depress the brake pedal, the spring pressure is overcome, and the switch is CLOSED, causing electrons to flow to the tail lights.

It isn't rocket science.

 

Aloha all,

First post here. Also my first jeep.

As far as this $10 stoplight switch goes, I know what one looks like. I also know my brake lights have failed. Somehow I can't seem to locate the switch down there in my 'new' jeep. (82 cj5)
I'm usually not blind and stupid (at the same time), so I'm left guessing that the part is not there? This wouldn't be something that would actually be found OVER the steering column? Seems way to far up to have to look. Had my head pretty wedged up there (the jeep!).

Heck - I may even try to upload a pic here. Not sure what the size limits are.

Anyway, Mahalo in advance!

P.S. (message edit) - I did purchase both the Chilton and the Haynes books today. No pics or good descriptions of this particular part.

--Rob

 

Sweet island rig you have there! I miss Oahu...

You won't find this type of switch on your CJ. It was only used for a few years (74 and 75). As someone else mentioned earlier, I think they are being used on TJs, but I don't have enough $ to get close enough to one to check!

The one mentioned here mounts on the driver's side of the brake pedal.

Check your IMs...

 

Thank you for the quick RE. I looked on the site you sent me. No luck. Upon further review though, I think I've found where this "missing?" puzzle piece might belong. See pic:



Anyway......yes, this is truly an "island ride" in it's current condition. The kid I got it from left the island early (he left Maui, NOT Oahu, Oahu bad, Maui No Ka Oi), and he did not seem interested in keeping much at all in working order on this jeep. Think I hosed out at least a carton of cigarette butts etc. from the floorboards last week.
So it's that kind of deal.
Just trying to get this CJ in manner that gets me the safety sticker and then maybe show her a tiny bit of TLC.

 

Don't know about an '82, but the '77 uses a switch like a big pushbutton that the pedal arm pushes against. There's a picture of it in my factory manual. Your local Napa should be able to get the switch for you.

If you can, take those aftermarket manuals back and buy a real Jeep factory manual. More money, but worth it. http://www.thejeep.net/catalog/prod...21&PHPSESSID=a2394747acb78fc2c81957101b8a19ca

 

Well thank you much timgr. I already took the plastic off these comic books of course. No matter - I'll be buying that real-deal manual you linked me to right after the rent check clears.

Figure the $85 book will pay for itself in eliminating some return trips to Napa to purchase my 2nd and 3rd wrong parts. Speed things up.

It already takes me a full day to fix anything. Then the 2nd day to fix the stuff I broke and did wrong. Another week or so for the knuckles to heal.

 

so then is the switch mounted to anything else or just the pin? i found mine playing bungee jumper under the dash, just dangling.

 

Many mahalos Mike!
I think I now see that indeed I have no switch, hanger, bracket, wires, socket etc.

I'll fab something soon after buying whatever switch NAPA sells.

I will NOT post pics of the final job though. Won't be pretty.

oh and......."Let's go Redwings! Clap, Clap, ClapClapClap!" (Originally from Detroit, stuck on this island now.)

 

Yes, it is a plunger type switch. The cotter pin that keeps it from sliding off the stud on the "pedal tree" is key. I know this because after the first trail test ride my switch half slipped off the stud and my brake lights weren't working. After 10 minutes of troubleshooting I found the culprit. Now I carry some spare cotter pins (along with the myriad of other spare stuff for "just in case")

Funny, i have gotten mine wet several times so far and it still works fine. Glad to hear it is only $10 to replace, though. Often those little electrical doo dads are spendy.