Right Brake Light Malfunction

[Tomnistuff]

First, let me say that I'm a mechanical engineer, NOT an electrical engineer.  I spent my career on automobile powertrains, (making them go), not making them stop.

My right hand brake light flashes very rapidly, about 5 times per second.  This happens as long as the battery is connected and the #1 fuse is installed.  Removing either connection will stop it.  Nothing else seems to stop it.

The brake light bulb is an LED, but it is the right hand "brake" light only, not the turn signal and not the other brake light.  It should have no relation to the electronic flasher.  When I turn the key on, the turn signals and all the other lights work correctly.  The left hand brake light does not do this.  It flashes with the key on or off.

Have any of you any experience with a symptom of this kind?

If the answers are no,  I will start an investigation to "diagnose" and test to eliminate possibilities, isolate the problem, and document it in detail.  The things I've read about misbehaving brake lamps is that they appear often to be related ground problems and to "feedback".  I don't know how anything could result in this misbehavior so I'm begging for ideas or experience of others.

Tom Kizer

[Tomnistuff]

Eureka!  I removed the right tail lamp housing and found nothing unusual.  I decided to reinstall the incandescent brake light bulb to see if it made a difference.  When I removed the LED bulb, the left hand side started flashing even faster instead.  I put the original incandescent bulb in the LED bulb's place and the flashing stopped.  Since the two LEDs flashed fast and one LED flashed even faster and one LED with one Incandescent didn't flash at all, I concluded it was resistance related - less resistance = faster flashing.  Apparently the Pagoda has a bulb out warning system for the brakes as well as the turn signals.  HYPERFLASH!

I contacted Superbrightleds technical support and talked to them on their chat room.  They confirmed that, based on the behavoir, it seemed load related and that adding a load resistor to each LED bulb is probably the only solution - even for the brakes.  I don't need it for the turn signals because I have already installed an electronic turn signal flasher.

It remains simply to install and verify when the resistors arrive.  If we're wrong, I'll have to start over.

Tom Kizer

[Tomnistuff]

I didn't get any comments or suggestions, but I proceeded to run the experiment anyway.

I had concluded, based on my bulb swapping, that on the brake circuit, one LED on one side and nothing on the other side caused the fastest flashing, without the ignition or lights even turned on.  When another LED was added to the "empty" side, the added resistance reduced the speed of the flashing by about half. (remember this is a brake light, turn signals and all other bulbs are not turned on.  The key isn't even on.  When I replaced one of the LED brake light bulbs with an incandescent bulb (1057), the flashing stopped completely.

Therefore the speed of the brake light bulb flashing (right bulb only in every case) was related to the resistance in the brake light circuit.  Low ohms equals fast, higher ohms equals not so fast and higher ohms yet equals no flash at all.

I added (1) 6 ohm, 50 watt load resistance in parallel with the one brake light LED bulb that flashed and all flashing stopped.
Further testing reveals that all the bulbs on all corners operate as intended under their correct operating conditions, determined by the light switch, turn signal switch, ignition key and brake pedal.  Only one bulb is not currently working under any conditions - the right front parking bulb.  It's the one that operates with the rear parking bulb when you need to park on the left side of a busy street at night.  That bulb needs its socket or its ground wire connection cleaned.

I've never heard of this problem before, and based on the heavy interest the problem drew (none), no one else has either.  Anyway, it's nice to have a solution, even if it's a "fake" problem.  "Fake" things are popular these days.  The right bulb uniqueness probably has to do with a slight difference in the drivers of the two bulbs.  I don't have the time or interest to explore the anomaly.

On to other things.

Tom Kizer
Levis, Quebec, Canada

[Rolf-Dieter ✝︎]

Hi Tom,

I too had a right hand breake light issue, only mine was a loose lightbulb connection that I found after disassembly of the housing. Mind you it is still ongoing and from time to time I have to get back in there to but the lightbulb back in. I keep parking backwards to store windows or other glass buildings so I can check it from time to time. Perhaps I need to have a closer look as to why this keeps happening. It is frustrating to say the least. I can feel the frustration you must have gone thru with your rapidly breaklight flashing, after all a Pagoda was never used as a police car ~grin~

Glad you resolved the issue, well done!

As for "Fake" don't worry ever the so called US President has a Fake painting LOL

---->  http://nypost.com/2017/10/20/trumps-renoir-painting-is-a-fake-museum/

Best,

Dieter

PS. Sorry you missed PUB this year, perhaps next year.

[JamesL]

Fascinating
Fun to find out that there's a "brake light out" but if you have to go to the back of the car to see the flashing, surely the fact that one light isn't working is apparent to the observer pretty quickly

Unless the flashing is to make the remaining brake light more visible to other drivers. In which case, chapeau to Sindelfingen.

[Tyler S]

Because the brake lamp circuit is seperate from the other lighting circuits, the only explanation is there is some sort of transient voltage on the line. Adding a load resistor or an incandesant bulb is enough to pull this transient voltage to ground and keep the LED from lighting.
Try disconnecting the brake lamp switch under the brake pedal. There could be some sort of conductive debris inside the switch (grease contaminated with metal from years of switch actuation)
If the flashing stops, replace the switch.

[Tomnistuff]

After some additional thinking, I think Tyler S. is right.  The clue may be that when I first noticed the flashing - battery connected but everything else off, I quickly started pulling fuses starting with #1.  That's because I once almost burned a 45 year old Ferrari to the ground due to an electrical fire.  It took months to get the car back to its pre-fire state.  A little paranoia goes a long way to provide peace of mind.

When I pulled #1 fuse, thinking I would have to pull several before finding the right one, the blinking stopped.

I looked at the electrical schematic and found that #1 should not have had an effect.  The brake lights are on #5.  I went back and installed #1 and pulled #5 but it still blinked.  Somewhere in the system, there may be a transient voltage from #1 to the brake circuit, unless that's the circuit that detects failed bulbs (if that circuit even exists).  Even though things now work correctly, when I get a chance, I'll go back and check the brake light switch.

Remember, I'm over my head.  I'm a gear head, not an electrical engineer.

Tom Kizer

[fosdicke]

 Always a good start is to Check grounds at tabs in trunk  and the  Diodes in  Tail Light housing.

[ejboyd5]

Just for S & G, put the LED lamp in the brake light socket on the other side and report your findings.