Brake light problems (and switch location)

My '69 CJ5 recently had it's brake lights quit working. I checked the bulbs; they look brand new and the filaments are intact. The left light has more wires than the right, and a spot for a tiny "fork type" fuse, and there is no fuse there. Thing is, there never was, as this is the first time I've removed the brake light covers. I even had the wife pump the brakes while I bridged the fuse gap with a wire to no avail. The PO stated he had "chased down all the electrical 'demons,'" so needless to say there are a few questionable wiring choices, this possibly being one of them. My conclusion is that the fuse is unnecessary (remember this Jeep has no fuse box, just random in-line fuses underneath the dash and hood).

The turning lights work, as do the running lights, front and back. So I'm guessing the brake light switch, but I CANNOT find the damn thing! I've searched this and many other forums, and people have stated it's connected to the pedal, underneath the dash, etc. (on other Jeeps), but that isn't helping me. My brake pedal pivots on an arm below the floorboard just behind the master cylinder as opposed to the type that hangs from an arm above the pedal. There are no wires between the pedal and floorboard, nor can I find any wires or switches connected anywhere to the brake pedal and rod itself. I don't see any connected to the arm it pivots on; the only place I can see any possible wires is one in front of the master cylinder where the brake line connects to a small metal box that splits it into two lines for the front and back brakes; there is a corrugated metal line coming out the front side that goes into the engine compartment, but not toward the back. I followed the wires from the brake lights, and they run into the engine compartment and meet up with some other wires coming from all different places to split off into various places in the engine compartment. Moreover, it seems that in some place between the brake lights and the place where they meet up with other wires, the wires are spliced with some of a different color, making tracing difficult.

Bare with me, for I am obviously a novice at this kind of thing. Am I missing something really obvious? I can post pics if necessary (it will help if you tell me what to take pics of), but I'm really getting frustrated...not to mention growing tired of helpful motorists pointing out my lack of brake lights on the road (and fear of getting pulled over).

Thanks in advance.

 

Your master-cylinder is the underfloor single reservoir type?

Should be a kinda thick disk mounted to the end of the master-cylinder opposite end from the rod. Not exactly round, looks like you can put a fair sized crescent wrench on it to turn it. There are two terminals pointing toward the front bumper. Bullet type. One wire has 12v power to it and the other runs off either to the rear and the brake lights or connects to the turn signal mounted to the side of your steering column.

 

If yours is a V-6 model, I may be all wet. Mine is a '60 with the underfloor master-cylinder.

 

two prongs on front of master cylinder are for the brake lits 12 volt power line to one prong and wirer to turn signal switch
see wiring schematic for turn signal switch. you can find it on here

 

Ok, research says I am all wet. In '67, evidently the feds decided they had a better idea and all vehicles had dual reservoir master-cylinders installed, with the front and rear brake circuits separate from each other.

The brake switch is now either up on a bracket coming from the dashboard toward the firewall that has a switch mounted in it that is held in the off position by the brake pedal arm (which with through the floor pedals is impossible) or mounted in a side or bottom fitting on the master-cylinder it's self. Which means I am not much help.

 

Well, now.
To confuse the issue: Rockauto.com shows that the '69 CJ5 in both the V-6 and I-4 configurations uses the brake switch shown in Boiler's picture.
The two nubs are the electrical connections, and it does not matter which is the hot lead.

 

Look on the frame rail installed in line with the rear brake line. It's a pressure switch with two terminals on top.

 

Get you a test light and go down to that switch in the brake line and see if one of the two wires light up the tester. You don't have to turn the key on or push the pedal. One of these wires should be hot all the time. If not then you have a blown fuse or bad wire/connection. That hot wire will be fed off the back of the headlight switch. If you have power on one wire then test the other wire with the pedal down hard. If no light then bad switch. If you have power then follow that wire up where it connects into a coupling at the turn-signal switch wires. You will
probably find a bad connection at this point or you may have a bad turn signal switch.


Correction (If not then you have a blown fuse) The po may have put in an in-line fuse as some people do, however it should go directly to the protected side of the circuit breaker which would be the same point where the breaker mounts to the headlight switch.

 

if by chance you have a dual mc . then you will have two pressure switches . one mounted up front on driver side frame rail behind shock tower (front) and one on inside of frame rail just behind the pivot for your pedals (rear) . but then again my is a 71 . these wires are like you said 12V inline fuse to pressure switches and then to your turn signal switch . . do the turn signals work

 

Mine has the dual reservoir and it has 2 switches, one up front near the radiator, one on top of the frame rail near the clutch/brake linkages

[/IMG]

[/IMG]

 

Twin2 beat me to the punch

 

thanks homersdog . didn't need to get pictures

 

yup, as stated before, check the little inline switches, the problem on one of my jeeps was corroded contacts on the switch.

 

I have same two as the previous folks mention. FYI, I bought two new ones, and connectors in boxes for later still. Other issues facing the Heep. But I've taken some Emory cloth and shined the old contacts on the one near radiator, and in the switch, I used a wire wheel on the dremel. Watch out or you will auger out the grooves. I tightened the connector by taking a 8" zip tie and jamming it in above, then side cutters to trim. One side needed two layers.

I found them online. Some one had them for like $8 each, but I think summit had them with connectors for $15... And the connectors I couldnt seem to find for some reason, may be my lack of connector doo-hiki language skills.

Mine to suffer the eventual death by a thousand splices...

Now I have faint brake lights. Will do the other one soon, as my weekends are more open now as I had the fortune to end my deer season on the opener successfully after a five hour hike/sneak, but I digress from the prob I have... The PO used ATF to keep things from rusting during long sit spells... I have an entire system to redo.

 

Wow; you guys rock...I really appreciate the in-depth replies. OK, I feel pretty stupid for missing it now. Thanks, homersdog, for the heads-up; mine was right next to the radiator, too. FYI I have a single reservoir (and a V6 since someone asked). Here's a pic (can't figure out how to hotlink from dropbox... tags aren't working.

[url]https://www.dropbox.com/s/mjhotmudvztfh2n/Photo%20Sep%2017%2C%205%2028%2048%20PM.jpg[/url]

Now, is this just a pressure switch that screws into that fitting? It didn't budge much, but I didn't feel like forcing it since I wasn't sure if that whole fitting has to be replaced.

Pretty sure this won't work, since it looks nothing like it:

[url]http://www.quadratec.com/products/55217_00.htm[/url]

This looks like it if you can decipher the horribly-exposed photo but says its for older models:

[url]http://www.quadratec.com/products/17238_01.htm[/url]

And I guess I can bet on fluid spraying out when I pull it out and thus have to bleed the system some, or maybe not?

 

As a side note, I don't have a multimeter (I know, I know), but I do have a test light...however, it has one probe and then a wire next to the light (not the cigarette lighter plug-in type). Any help? I tried hooking the wire next to the light to exposed metal on the clip of my battery tender, and got nothing on either one. There are two separate wires that seem to be running to both of the back lights, but it's hard to tell with the plastic harness, so I suppose one must be a hot wire back under the dash. The contacts seem fine, but the ones on the wires are suspect (cleaning them with a wire brush didn't help).

 

You can put a test light across a switch. if the switch is open, the light will be on, if the switch is closed, the light will go off. Also you can test each side of the switch to ground to see if it has power to it in the first place.

 

oh and yes, it just unscrews like a pipe plug. I think it is 1/8" NPT if i remember right but don't hold me to that.

any time you open a brake line it needs to be bled. Sorry.

 

OK, so I tested both terminals with the keys on and off and with the brakes on and off, and got nothing with the test light or multimeter. I also tested resistance across the terminals, getting infinity with the brakes off, and variable (but steady, anywhere from 2-80 ohms since I don't have clamps on the leads) with the brakes on. I'm guessing that this means the wiring is bad, obviously. I'm just a little unsure how it's wired. The hot wire is getting 12.8V, and the bulbs are definitely good after a resistance check (3 ohms). I didn't test the voltage hitting the light bulbs with the brakes on, but I'm assuming there is none on both sides since neither light is working. So I figure that the switch is good, and the wiring has failed somewhere between that terminal and the brake lights, somewhere before the wire splits to go to the lights.

Before I **** myself off trying to find it, is my judgment sound, and do you guys have any suggestions on how to go about finding the culprit? I'll post pics of the brake lights without the covers later if it makes any difference.

NOTE: p i s s gets censored? XD

 

X2, My 70 also had two of them. One on the frame rail near the shock tower on the drivers side and one in the line behind the master cylinder inside the frame rail on the drivers side. I left out the one behind the master cylinder during restoration and am only using the one up front on the frame rail.