My deuce lost her brake lights.

[RedbeardTheZombieHunter]

I skimmed the TMs but once again, I guess I didn't use the correct terms or for whatever reason couldn't find what I was looking for.

I noticed a few weeks ago that my brake lights weren't coming on when I stepped on the brake. Yes, I had the 3-lever switch turned to "stop light".
I got under the truck a few minutes ago and pulled the plug on the stop light switch on the airpak, then turned on the master power and set the 3-lever to "stop light", and checked both leads with a test light for juice and nothing on either lead. After visually inspecting the harness for chaving and broken wires, the harness it's self looks dirty and greasy like the rest of the underside of the truck, but otherwise in good condition. All the other lights including the blackouts all operate properly, just no juice to the stop light switch. Common sense tells me the likely culprit is somewhere in the 3-lever assembly like a dirty or crusty contact point.
My question is, am I stuck to replacing the switch assembly, or can it be opened and cleaned/overhauled? Any advise (less the inflamatory comments) would be greatly appreciated.

 

[Flyingvan911]

The switch on the airpack probably went out. But, there are two versions. One actuated by the hydrolic fluid and one actuated by air. There are threads on here about it. The usual suppliers have them.

 

[RedbeardTheZombieHunter]

I got ya Flyingvan911, but in order for the switch to do it's job, there's gotta be 1 hot lead, and the other to the turn signal switch for flasher bypass and brake lighting. With the switches turned on, I got no power to the stop light switch on the airpak. That's the issue I gotta figure out.

 

[commandojeff]

I had my air switch out on my 5 ton when I bought it. I tested the voltage just like you and i couldn't get a proper reading. I think maybe my ground was not sufficient. Another SS member told me to get a wire and hook the two wires leading into the switch together. Just make sure you have rubber on your wire you test with haha. This makes sense because connecting a wire to both wires that go into the switch is doing the same thing that the switch does when air is dumped into it. This worked for me and my lights came on (get another person to see if they come on when you test). So I now know that everything before my switch is good. Just an idea...

Jeff

 

[Flyingvan911]

Oh. I got ya.

 

[RedbeardTheZombieHunter]

YOU DA MAN JEFF! I guess my test light had a bad ground or bad bulb, but I stuffed a jumper wire into the plug leads per your suggestion, turned on the power and the brake lights were lit. I guess I gotta get a brake light switch and a new bulb for my test light. Thanks for the suggestion! It worked like a charm.

 

[commandojeff]

Hahaha glad it worked out for you! I did the exact same thing. I'm pretty sure I didn't have a great ground when I tested with my VM.

 

[doghead]

Is your test light rated for 24 volts? You probably blew the bulb.

 

[armytruck63]

First, turn the battery switch on and make sure your three lever is in the stop light position. Next, unplug the two wires from the brake light switch under the truck and have a helper watch as you short across the two wires. I used the handles of a pair of pliers. If your brake lights come on then you have a bad switch.

I replaced the hydraulic switch, but this would be the perfect time to perform the the air switch MWO. You obviously have to bleed the brakes after changing the hydraulic switch.

 

[RedbeardTheZombieHunter]

Yeah DH, my test light has a 24-volt bulb, but either I didn't get sufficient ground on it or the bulb got boogered knocking around in the step box, but I cut a small jumper wire and stuffed the ends into the switch plug, then I turned on the hidden anti-theft switch, the main power switch and turned the 3-lever light switch to the "stop light" position and checked the brake lights and they were indeed lit. When I pulled the jumper out I stabbed my thumb with 5 braids of copper wire. OUCH!!!!! Final verdict: Bad brake light switch. I'll add that to the scavenger hunt list when I go parts hunting next weekend. Thanks to all for the advise and tips. It's sometimes difficult to come up with obvious answers when it's hot outside and ya crawl in hot dirt to get under the truck with a sore back.

 

[SMOKEWAGON66]

Hey RBZH...Until you get a new switch, why dont you make a temp switch that splits the contact between the two leads when you press on the brakes? I know you know a thing or two about electricity so Im sure it wouldnt be hard for you to do. I have been wanting to make my own switch that activates immediately upon depressing the brake pedal because whichever switch I have (the older style I think) always has a delay in it, and sometimes you have to give the pedal a second pump before you get lights. Also you have to be pressing pretty hard i.e. stopping. My brake lights do not light up on the soft snub braking like they should. Someday perhaps I will figure it out...Like when I figure out how to get the internals of those lights you gave me to work the way I want them to lol.

 

[RedbeardTheZombieHunter]

Not a bad idea Smoke, I just might do that. How's that project of yours coming?

 

[SMOKEWAGON66]

Not a bad idea Smoke, I just might do that. How's that project of yours coming?

Slowly...lol. The last major thing I need to do is get the troop seats sanded and painted. For some reason, Ive been dreading it lol. I still need to stencil the company and truck numbers on front and back and I should be mostly done with the major appearance stuff..mostly. Im going to get the troop seats done this weekend because next friday the 7th, I think Im getting a photo op for my truck with an F-22 on the flight line at Edwards AFB. We shall see how that goes, and of course I will definitely post the pic here when I get it.

 

[wilsonmotors]

i have done the same on my m35 and still dont have brake lights when i jump the brake switch anyone one have any ideas

 

[phil2968]

I did this to mine has a temporary fix back in March! It is still working. I may leave it but add some hose clamps instead of the wire ties. I had the sealed microswitch so I put it to good use. I had to drive the truck through Orlando Florida the next day and could not get the brand new hydraulic switch not work all the time. Did not want to get in stop and go traffic with no brakes lights!

 

[swampzr2]

Can someone explain how this works as a switch?

I did this to mine has a temporary fix back in March! It is still working. I may leave it but add some hose clamps instead of the wire ties. I had the sealed microswitch so I put it to good use. I had to drive the truck through Orlando Florida the next day and could not get the brand new hydraulic switch not work all the time. Did not want to get in stop and go traffic with no brakes lights!

 

[212sparky]

It looks like it hits the floor to open the circuit. Once the peddle is pushed the lights come on.