Dan,

It's not often I can find something in my Carrera that I would concider a engineering issue. But this brake light system does seem like it could possibly be improved. It's great to chat about this stuff figure out what the problem is (FIRST) then find a better improvment for our cars.

Thanks for the input.

 

Thank You Peter Zimmerman for your in field and life long mechanical experience,

I concur, there is absolutley no substitute for a quality shop like yours and your clients are lucky to have you. My wrench has saved me from so many issues I can even count, actually I did 174 to be exact.

Also my compliments on doing a fine job on those brake light switches. It is just that I have bit of OCD and could not stand for the BLS malfunctioning within 10 weeks or even after 10 years. I don't know about others but I plan to take my baby to the grave or when I become so old myself that I can no longer drive her and reluctantly sell her. I would hate to hear my baby got rear ended due to a failed BLS, it would just break my heart.

If I may, I will address your points: [1] "False Warnings" our BLS Arc Suppresor (BLSAS) will aboslutely not give a false warning due to component used. If anything, the BLSAS gives off an audible click to indicate to the operator that the BLS is functioning ergo Brake Lights are On. Most do not have an after market LED third light like mine to see the lights are working so the audible click is a comforting feature. [2] "System Failure" I assume you mean in the case of sudden engine shut off while driving, as long as there is current flowing from the battery, the BLSAS will operate the BLS's as designed. The BLSAS reduces the amperage but the 12 Volts remains unchanged. EE's please verify. According to Bentley Guide the dedicated amperage is 8 Amps.

SCarCeller,

I too considered the mechanical switch route but even they have issues such as adjustment/maintenance schedule but the most concerning was the possibility of a debris lodging in between the contacts which would result in no Brake Lights at all. I drive agressively on the street and from time to time I find my lost stuff all the time all over the place in the cab. For me, I would rather have slow brake lights then potential for no Brake Lights at all. This is my humble 2 cents.

I've even considered the motion mercury activated third light but talk about false readings. I would have people really pissed that they would think I am riding my brakes.

Douglas Bray,

Air in the Brake System will have little to no effect on the BLS's because the switches only require less than 50 Lbs of pressure as I recall. As long as Brake Fluid covers the BLS's they will always activate under minimal pressure. The reason one has to apply more pressure is to force the contacts to actually to meet inside the BLS over the deposits and melted plastic composite.

I will re-check my notes about the actual pressure required for the BLS. I was going to develop a low pressure switch only to be told by my Electrical Engineer it was not the issue. Of course you would want to rid all air in the Brake System.

Steely,

Another EE, nice.

Pictured is a combination of Carbon Deposit Build up and Melted/Bubbled up Plastic Composite at the Contact on the right and deposits on the retangular metal piece. The contacts are fixed and the only components that moves inside the BLS are the retangular metal piece to close the circuit, rubber plunger controlled by pressure and spring to push the metal piece away from the contacts when pressure is off.

I too was concerned not to effect the OEM 12v dedication but my EE assured me the BLSAS will only suppress the arcing effect in the BLS via lowering of amperage.

SCarCeller,

Yes indeed, we have noticed the BLS does turn on less than a second but with our device it will nolonger get progressively slower. One of my customers actually took 4 seconds under normal braking to activate his damaged BLS's. Once he replaced both BLS's and installed the BLSAS it activated within less than a second. 4 Months later he reports it is still less than a second.

Your example of the light switch is right on the money. If one takes apart a well used light switch, one will see the carbon deposits. Now imagine the contact surrounded by plastic while the arcing occurs. This is what is happening to us unlucky guys with malfunctioning BLS's.

 

Here Here

 

Hey Sal (Resident EE)

Any pics of your disected BLS?

 

Another reason why Mechanical BLS's is not the best fix for our babys: http://forums.pelicanparts.com/showthread.php?t=409694

 

Draco,
I'm out of town for the week in Norway will post next week.

 

Cool, that would be great!

 

Basically, by false warning I mean somehow triggering the light on the dash when there is no problem with the brakes, or worse, failure of the modified circuit to recognize a system failure and not turn on the dash warning light. The switches are wired to recognize an internal pressure drop in the hydraulic system, and if all of the fluid from either the front or rear circuits is lost, the dash light turns on to warn the driver that loss of braking efficiency is about to, or already has, happen.

Please don't misunderstand me, I have no problem with what people do with their own cars. I worry about an unsuspecting buyer of a car with modified circuits that could lead to an unanticipated failure.

Back in the day, before I opened Red Line, I worked at a P&A dealer as their P-car specialist. One of the Audi techs couldn't figure out why the brake warning light on the dash of an Audi sedan kept coming on, so he cut the wires to the lamp and shipped the car as "fixed". A couple of months later the car was towed in with moderate to severe front end damage, and the owner's claim that the brakes had failed. Our service writer confirmed that the brakes failed, checked the car's history, found the cut harness, and went to whisper in the Audi mechanic's ear that he had ten minutes to vacate the property.

As I see it, modifying a system that supports a warning device can have its hazards, and that's what I worry about when I read a thread like this. It's nothing personal, only a concern for the guy driving the car!

 

Oh No Dr Z.

You are absolutely not misunderstood, I misunderstood your concerns. Please forgive me.

I now totally understand your point/s and agree with you about POS's and Crooked Wrenches who brutalize our babies. My own experience is when the POS used JB Weld to keep the the Reverse Lock Out open causing me to grind her gears from 5th.

If I may explain, our device in no way interupts the BLS's Hydraulic Mechanism. If GOD Forbid a sudden pressure drop and/or no pressure exists in the hydraulic system, our BLS ARC Suppressor will not and can not active the brake light switches or anyting for that matter especially the Brake Fluid Level Switch located on the Master Cylinder Filler Cap.

The BLS Arc Supressor is totally dependant on the Hydraulic Pressure of the BLS's. In Fact the OEM Wiring is not hacked into in any manner shape or form.

According to Bentley Manual Page 970-64, for an 1985 Carrera, The Brake Light/Switch System is dedicated to Fuse Box 1, 8 Amp Fuse #4. The Brake Fluid Level Switch is not part of this dedicated system. Please someone correct me if I am in error.

Your story of that Retard Wrench is horrible and he is damn lucky he did not kill anyone in the process. It is no wonder that his fix failed, simply cutting off the harness is the worse thing anyone one even a supposed qualified mechanic can do without knowing the ramifications of his simple minded action.

Please rest asssured we have thoroughly reseached and I have tested personally on my own baby to insure our device works the way it is supposed to. She still has on our BLS Arc Suppressor and she has operated with our a hitch or hickup. In fact, PPI from RennSport, Torrance California gave my Brake Lights the thumbs up and was suprised it worked so well. I also made certain that an owner could always go back to OEM BLS system without worrying about having to replace any original OEM Harnesses or Devices.

You see, our BLS Arc Supppressor does not modify or effect the brake fluid level warning system.

Again a Sincere Thank You PZ, it is comforting to have a Guardian Angel to protect us and our Babies.

 

Draco,

I destroyed the first switch trying to open it but I got the second switch opened very cleanly and here is what it looks like:

You can clearly see that the '+' side of the switch is completely toast, I'm surprised it did not weld it self closed! Now with the new switches and the addition of my relay the brake lights work great.

I really think these switches are not designed to handle all the current required by the brake lights, the arc damaged contacts seem to indicate this is the issue with the design.

 

Hi Peter,

After close look at the wiring diagram for the 84 Carrera it seems the brake light in the dash is simply wired to the brake fluid reservoir switch that is on the cap you use to fill the reservoir. The brake light on the dash does not appear to be wired to the 2 switches for the brake lights. So the master cyl has 3 switches on it, 2 for the brake lights and the third to simply indicate brake fluid is low (this one is on the cap). It seems the dash light simply comes on only if the reservior is low.

I could be wrong but this is what I see from the 84 wiring diagram.

 

Ok, so next question, somewhat related...

I have the 2-pole, narrow-connectors on my '84. The Pelican replacement switches are 2-pole, WIDE connector pattern, and they mention, "an adapter may be required". Of course, they don't seem to list one.

So, does anyone know of one? I have gently removed the spades / terminals from the white plastic connectors, and temporarily put them on the switches with black tape around them to prevent inadvertent shorts. I will be putting Draco's relay kit on this weekend & figured I'd ask for those just replacing their switches.

 

I found this issue when replacing my master cylinder recently. This was my solution

http://forums.pelicanparts.com/showthread.php?t=399703

 

See post #15 above, I simply bought VW switches, much cheaper and seem to work just fine with my relay mod.

 

Wow, that is a pretty bad one. Thanks for posting