Brake lights wont work after bob job

[jake1086]

OK so ... you guys are gonna laugh (this means some of you are going to yell at me)

but when I bobbed my deuce I had some "friends".... "helping" and they rushed me into just cutting the wires instead of unbolting the mounts and unplugging the lights...

So while one of these "friends" was helping me put it all back together I had 3 hott wires (now you're really gonna laugh/yell) from where the trailer connector was cut off well I had it figured out and he was arguing with me because he's a dill hole. And while I was pushing the brake pedal to show him we had 3 hot wires I'm pretty sure he touched two of them together or something and now there are no hot wires for the brakes

and it was working so well we had our blinker wires worked out and they are also the brake wire's correct? ... so I have tails and blinkers but no brake lights...... what did he screw up are there fuses on this **** thing????

 

[porkysplace]

Do you have power to the brake light switch ?

 

[steelandcanvas]

Those aren't "friends". The only fuse is underneath the little cover on top of the fuel tank and it's for the in tank lift pump. As Porky suggested, you need to see if you have power to the brake light switch, we can go from there. Unbolting the lights as you suggest would have been the correct way to get them out of the way. Get some other "friends" that will listen to you.

 

[jake1086]

where is the brake light switch I was under it crawling around but didnt see anything is it right off the pedal underneith? or on the air ... thing or hydraulic res... booster... thing...

 

[porkysplace]

Either on the airpack/master cylinder or if upgraded to a air switch in the airline between the brake pedal and airpack.

 

[TMNT]

I normally don't get involved in these discussions but I can't help but wonder how you can have the tools and skill to bob a deuce, but not even know where the brake light switch is, or how to troubleshoot the electrical system. You actually set out to drop an axle, cut the frame, and replace the bed without being thoroughly familiar with the vehicle and all of its systems?

That just doesn't add up to me.

 

[doghead]

An easy way to find where parts are is, simply browse through the pictures in the -20P or -34P TMs!

You can even search by word, when viewing them as PDFs.


One more way to find it is, simply search this site. Surely there has been a few pics posted in the last 7 years.

 

[porkysplace]

Pictures in this thread ; [h=3]Brake Light Switch Upgrade Question[/h]

 

[jake1086]

the problem doghead is I didnt even know what I was looking for. Does adding another thread for people to find (since when I do search I usually cant find crap) really hurt?

Thanks Porky

TMNT, I liked raphael And The mechanics of bobbing a deuce are.. simple compared to some of the stuff I've put together (think 2 460's built end to end, custom 455 mud rail, monster trucks things like that)

 

[welldigger]

Probably fried your switch. Look on the air pack or MC and find something with 2 wires coming out of it. Jump those 2 wires together and see if your brake lights work. If they do you have a bad brake light pressure switch. If they don't still you have another problem.

 

[TMNT]

TMNT, I liked raphael And The mechanics of bobbing a deuce are.. simple compared to some of the stuff I've put together (think 2 460's built end to end, custom 455 mud rail, monster trucks things like that)

Yeah, I picked up that handle from my modded FJCruiser. It's army green and from the front people say it looks like a ninja turtle. Tie a red bandana to the radio aerial and its Raphael!

Like I said, I figured that you had the tools and the know-how. The brake light system on the deuce is pretty simple.

The master cylinder/air pack is inside the left frame rail, below and slightly behind the driver's seat. There are 2 kinds if brake light pressure switches: The hydraulic kind is screwed into the from of the MC and has two wires in a round plug about 3/4" diameter. Pull those 2 wires and touch them together with the accessory switch ON. If the brake lights come on, the switch is bad. If no brake lights, find out why there is no power to the switch.

The other kind of switch works with air pressure and it should be in an air line near the MC. Look for a Tee connector in an air line with a round body switch with 2 wires connected. Troubleshoot it the same way as the hydraulic switch.

The brake lights and turn signals work (have power) only when the accessory switch is ON. That's the power switch you turn on to start the engine.

 

[doghead]

Does adding another thread for people to find (since when I do search I usually cant find crap) really hurt?

My comments/suggestions had nothing to do with you "adding another thread".

I was just offering help. Even if it does not help you, it may help others reading this(now or in the future). I was just trying to help.

 

[jake1086]

Thanks TMNT, sorry doghead sounded more... rude. I'll try to search more often but it really is a pain in the arse google search works better than the sites own search

 

[porkysplace]

So have found the switch ? is it working ?

 

[jake1086]

been kinda busy I might try and get to it tonight. I'm sure that's what it is. They were working and then douche touched two hots together I'm willing to bet and fried the switch wheres the best place to get one of these guys eastern surplus? OR will napa trucks carry something like this? (wishful thinking I know)

 

[TMNT]

Pretty sure NAPA won't have this one. They're about $40 from a few sources. Try Erik's Military Surplus.

I don't get why touching 2 hots together on a single source, common ground DC system would cause a problem.

I would think your buddy shorted the supply (hot) to ground and that over-loaded the switch. And that could only happen if the master switch was on and the brake pedal was being pushed. That could have burnt the contacts. Even if he touched the brake light supply line to another hot, it would have simply backed 24V in to the switch where it would have done nothing.

I suppose that regardless of how it happened, it happened. The switch is cheap and readily available.

 

[doghead]

Switch is easy to test.

The signal switch could have burned out.

Best bet is to diagnose it.

NAPA does have a switch that will fit, but it is not rated for the pressure or the DOT5.

Now is a good time to improve safety and convert to an air actuated switch.(the military did this too)

 

[73m819]

Yeah, I picked up that handle from my modded FJCruiser. It's army green and from the front people say it looks like a ninja turtle. Tie a red bandana to the radio aerial and its Raphael!

Like I said, I figured that you had the tools and the know-how. The brake light system on the deuce is pretty simple.

The master cylinder/air pack is inside the left frame rail, below and slightly behind the driver's seat. There are 2 kinds if brake light pressure switches: The hydraulic kind is screwed into the from of the MC and has two wires in a round plug about 3/4" diameter. Pull those 2 wires and touch them together with the accessory switch ON. If the brake lights come on, the switch is bad. If no brake lights, find out why there is no power to the switch.

The other kind of switch works with air pressure and it should be in an air line near the MC. Look for a Tee connector in an air line with a round body switch with 2 wires connected. Troubleshoot it the same way as the hydraulic switch.

The brake lights and turn signals work (have power) only when the accessory switch is ON. That's the power switch you turn on to start the engine.

WRONG, BRAKE LIGHT switch powers from the 3 lever which is hot ALL the time, you can have 4 ways (brake and turn signal bulb) or any other lights (BO, ECT,) with the assessory OFF.

For the AIR brake light switch to work, there has to be at least 60lbs of of AIR in the system.

I am betting the problem is NOT the brake light switch but the 3 lever, this has c/bs inside, shorting the wires fried something in the 3 lever, we had the same thing happen with SWISS'S restored m62, while working on the wiring something got shorted and ending up frying the 3 lever which we replaced then everything lite up fine

 

[TMNT]

Yeah, I don't know why I forgot the 3-way switch. That's what I get for posting while driving.

I assume "c/bs" means circuit breaker?

He still doesn't know whether he has the air switch or a hydraulic switch for the brake lights, so we don't know if air pressure was a factor or not.

I guess my main point was that touching 2 hot wires together on this truck would do nothing. Take a short wire and touch one end to the positive battery terminal. Now touch the other end of the wire to the same terminal. Nothing happens. The potential is equal so no current flows. It would be the same touching two hot wires together.

In order to short out the brake light circuit, the 3-way would have to be on, and have the brake pedal depressed (with air in the system for the air switch) and have the hot wire go to ground somewhere downstream of the pressure switch. Otherwise, none of the brake light supply wires would be hot and it wouldn't matter if they touched ground or even another hot wire.

In that case, it could be the 3-way got fried or the pressure switch fried, or both. I don't know what the current rating is for either switch, or which on is more likely to survive a dead short.

I think we're back to good old fashioned troubleshooting. He needs to determine if he has voltage at the supply side of the pressure switch. If YES, check the pressure switch output with the pedal pressed, or ohm out the switch to see if it closes with the pedal pressed.

If no voltage to the pressure switch, it's probably the 3-way switch. Do ANY of the lights work? Headlights or turn signals?

 

[porkysplace]

Yeah, I don't know why I forgot the 3-way switch. That's what I get for posting while driving.

I assume "c/bs" means circuit breaker?

He still doesn't know whether he has the air switch or a hydraulic switch for the brake lights, so we don't know if air pressure was a factor or not.

I guess my main point was that touching 2 hot wires together on this truck would do nothing. Take a short wire and touch one end to the positive battery terminal. Now touch the other end of the wire to the same terminal. Nothing happens. The potential is equal so no current flows. It would be the same touching two hot wires together.

In order to short out the brake light circuit, the 3-way would have to be on, and have the brake pedal depressed (with air in the system for the air switch) and have the hot wire go to ground somewhere downstream of the pressure switch. Otherwise, none of the brake light supply wires would be hot and it wouldn't matter if they touched ground or even another hot wire.

In that case, it could be the 3-way got fried or the pressure switch fried, or both. I don't know what the current rating is for either switch, or which on is more likely to survive a dead short.

I think we're back to good old fashioned troubleshooting. He needs to determine if he has voltage at the supply side of the pressure switch. If YES, check the pressure switch output with the pedal pressed, or ohm out the switch to see if it closes with the pedal pressed.

If no voltage to the pressure switch, it's probably the 3-way switch. Do ANY of the lights work? Headlights or turn signals?

Did you read post # 1 ?