Brake Light issue

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John L
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Brake Light issue

Post by John L » Sun May 13, 2012 7:57 pm

Guys I could use a little help. I noticed my brake lights were out. Since the bulbs were good I figured it had to be the brake light switch. I bought a replacement from EI and just installed it. But, no luck. I have tail lights, turn and hazard signals but no brake lights. What am I overlooking? Does it matter which wires go to which spade bit on the switch? It's gotta be something simple but I can't figure it out. Any help would be appreciated.

Thanks

John

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pcolette
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Re: Brake Light issue

Post by pcolette » Sun May 13, 2012 11:14 pm

I think breaker #12 is for the brake lights so you may want to check that, although that doesn't sound like your problem since other lights are working.
The stop light switch is just a simple switch so it makes no difference which wire goes to which terminal.
The brake light bulbs are dual filament - any chance the brake filaments are bad?
Paul C.
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'73 Swiss 710M
'89 Puch 230GE
2002 MB G500

undysworld
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Re: Brake Light issue

Post by undysworld » Mon May 14, 2012 7:17 am

Is the switch positioned correctly, so that the park brake lever makes contact and switches it?

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berger
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Re: Brake Light issue

Post by berger » Mon May 14, 2012 8:13 am

Try cleaning up all them metal surfaces, spades etc. I did that and mine came back to life.
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John L
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Re: Brake Light issue

Post by John L » Mon May 14, 2012 9:43 am

 Re: Brake Light issue
Is the switch positioned correctly, so that the park brake lever makes contact and switches it?

Interesting question: I've read my two manuals and don't see a reference to positioning the switch. I merely screwed it in to the back of the master cylinder until it was tight. Please expound on your question. How should the switch be positioned?

As for cleaning it, good idea, especially for the spare. The plug itself is new and clean.

Any other thoughts? I can't imagine I have a cut or cracked wire; but anythings possible I guess.

Any input is appreciated. I'm pulling my hair out trying to diagnose it and the Pinz is dying to get back on the road.

Thanks again,

John

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pcolette
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Re: Brake Light issue

Post by pcolette » Mon May 14, 2012 10:09 am

undysworld wrote:Is the switch positioned correctly, so that the park brake lever makes contact and switches it?
I think Paul (undysworld) was referring to the parking brake switch at the rear of the Pinz. He may not have realized you were talking about the one on the master cylinder.
I'd connect the 2 leads at the switch just to see if the brake lights go on. If they do then the switch may be bad, even though it's new.
Paul C.
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'89 Puch 230GE
2002 MB G500

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Jimm391730
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Re: Brake Light issue

Post by Jimm391730 » Mon May 14, 2012 11:15 am

Is the switch positioned correctly, so that the park brake lever makes contact and switches it?

Interesting question: I've read my two manuals and don't see a reference to positioning the switch. I merely screwed it in to the back of the master cylinder until it was tight. Please expound on your question. How should the switch be positioned?
The brake light switch is a pressure activated switch, the switch closes as the brake hydraulic pressure builds. No adjustment is needed beyond making sure that there are no leaks.

I'm pretty sure that one of the two brake switch leads has 24V on it all the time, so that when the switch closes the brake lights operate; check for power. The other lead goes into the turn signal wiring and switches (emergency flashers and turn signals) as they have to "disable" the brake signal on the side(s) that are flashing; that lead does not go directly to the brake lights.
Jim M.
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Re: Brake Light issue

Post by undysworld » Mon May 14, 2012 11:39 am

Yup, sorry. I misread the original complaint, and was referring to the parking brake switch.

Never mind...

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David Dunn
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Re: Brake Light issue

Post by David Dunn » Mon May 14, 2012 11:48 am

Before everyone get carried away.. is your truck to Swiss specs ( circuit breakers), or standard Austrian ( fuses)? The brake lamps on a Austrian spec truck has it's own filiment in the tail lamps and Swiss combines with the brakes and turns in one single filiment bulb. On either type truck, short the leads together (at the brake switch) and see if the lamps come on ( with power switch on... and check breakers or fuses). If it works, bad switch... if not, try wiggling turn indicator lever, as Jim said there is a set of contacts inside the switch that allow the turn and brake lamps to work together.
Lastly, some people have mucked up their wiring trying to convert the amber brake lamps to red on Swiss truck, if isn't done right....
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David Dunn
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Re: Brake Light issue

Post by David Dunn » Mon May 14, 2012 11:51 am

undysworld wrote:Yup, sorry. I misread the original complaint, and was referring to the parking brake switch.

Never mind...
BAD Paul... now go to the corner and put your nose in it! :mrgreen:
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Re: Brake Light issue

Post by undysworld » Mon May 14, 2012 2:29 pm

I've even put on my dunce cap. D'oh! :(

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John L
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Re: Brake Light issue

Post by John L » Mon May 14, 2012 5:16 pm

David Dunn wrote:Before everyone get carried away.. is your truck to Swiss specs ( circuit breakers), or standard Austrian ( fuses)? The brake lamps on a Austrian spec truck has it's own filiment in the tail lamps and Swiss combines with the brakes and turns in one single filiment bulb. On either type truck, short the leads together (at the brake switch) and see if the lamps come on ( with power switch on... and check breakers or fuses). If it works, bad switch... if not, try wiggling turn indicator lever, as Jim said there is a set of contacts inside the switch that allow the turn and brake lamps to work together.
Lastly, some people have mucked up their wiring trying to convert the amber brake lamps to red on Swiss truck, if isn't done right....
Good questions and thanks for asking: It's a swiss vehicle, not Aussie. 1975 710M. It apparently had a conversion of the tail lamps and turn signals. The hazards and turn signals are amber and the brake light is red. The amber portion of the lens is at the top. I've had the vehicle since last August with no trouble. Recently a friend noticed my brake lights were out. So, I checked the bulbs and they were fine. There is a dual filiment buld for the brakes. (I guess tail light and brake light combination?) I ordered a new brake light switch and installed it. No luck with getting brake lights. I do have tail lights off of the same bulb, but nothing lights up when I push down on the brakes. Everying else works. I also had checked the breakers and they were fine. Horn and such that is on the same breaker work fine.

I'll try putting the wires together and see if that works. If not then I guess I'll check for power to the switch. If there is power then I guess check the switch itself. Any way to test the switch?

I guess it could also be a problem down stream of the switch and before the wire splits to go to both tail lights.

Any other thoughts? It's just odd that I would have a wiring problem develop overnight. I can see a switch failure, but to have a wire randomly go bad would be odd. If you have any other ideas, please let me know. I need to get her back on the road but don't want to risk it without brake lights.

One other question: someone mentioned that one of the wires from the switch goes to the hazard switch. Is this true? If so, and they are switched on the hazard switch, could this be the cuprit? (i.e. if I switch to two connections will it make a difference?) If I recall correctly there is a wiring harness on the hazard switch and two spade bit connectors. If the two wires that go to the spade bits are switched, could this be the issue? I'm just a bit lost with the wiring on this sucker. Lover my truck to death, but the electical can be a bit of a challenge.

Thanks for all the input.

John

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4x4Pinz
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Re: Brake Light issue

Post by 4x4Pinz » Mon May 14, 2012 5:25 pm

don't know if it has been mentioned but the electrical block on the rear passenger corner of the truck can cause symptoms like this. The wires get corroded and loose contact. A simple tester on both sides of the block will show if this is the problem.

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Jimm391730
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Re: Brake Light issue

Post by Jimm391730 » Mon May 14, 2012 6:04 pm

I have had brake pressure switches that took an "excessive" amount of pressure to get them to turn on; more brake pressure than I commonly used when coming to a stop. But in testing, a good leg turned on the brake lights while stopped. I replaced the pressure switch and the new one took significantly less pressure to operate, enough that I feel safe that the brake lights are activating properly.

So if you get brake lights when the switch terminals are shorted, then the switch is bad. If not, I'd suspect a single failure somewhere in the wiring back to the lights -- since your truck was rewired for red brakes, independant of the turn signals (correct?) then there is likely only one wire back to the brake lights that powers both left and right. Did they use the junction box under the truck at the back? Have you checked there for corrosion? Can you follow the brake lights wire back up to the dash?

General "divide and conquer" techniques work well here. Best of luck.
Jim M.
712W and 710M

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David Dunn
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Re: Brake Light issue

Post by David Dunn » Mon May 14, 2012 6:58 pm

Well John
First off , you’re going to have some very ticked off people at you :lol: .. It’s Austrian, not Aussie… completely different side of the world. And one drives on the wrong side of the road… and they says its the other that does :roll: .

Now that you have said that the brake lamps were taken out of the combined brake/turn circuit, it means you need to find the “new” wire from the front to the rear. There have been several different ways people have done it, and you need to see how yours was done.. Many times, people used the pink wire inside the rear lamps and wired them to the 2nd filament and disconnected that wire from the head lamp switch and ran a pigtail to the brake switch.

That was one way, you'll need to determine how the previous owner did it... first check the color of the wire at the brake light and follow it back to the front.

Happy hunting.

btw The pink wire was not used by the Swiss models originally.
.
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The Trojan Horse... the 1st Pinz used to covertly carry troops into battle .




ATL Pinzgauer XM 718K TUM(HD) 6x6 FFR (aka The Green Grail)

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