Flashing third brake light? Tips? Electrical experts...

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I've installed a flasher module inline with my Miata's rear third brake light. The Miata has a single bulb with two leads, + and - going to it.

The P5 has what looks like two leads going to it as well, green and black.
The Miata's is green and black as well.

I installed a working flasher module inline just as I did on the Miata and it does not work.

I'm thinking this has something to do with the multiple bulbs used on the P5.

Anyone have any ideas as to why this isn't working and how it could work?
 
ok I know absolutely nothing about the flasher module but here's my guess:

maybe the flasher module works like a turn signal flasher, and relies on heat caused by current drawn to expand and contract a fillament which completes and breaks a circuit. LEDs draw much less current than an incandescent bulb and would not allow this to happen

just a guess.
 
toucci said:
ok I know absolutely nothing about the flasher module but here's my guess:

maybe the flasher module works like a turn signal flasher, and relies on heat caused by current drawn to expand and contract a fillament which completes and breaks a circuit. LEDs draw much less current than an incandescent bulb and would not allow this to happen

just a guess.
Click to expand...

That would be easy enought to test by hooking a standard bulb up in series with the existing brake lights. Wire it up and see if it starts flashing. If it works you can just hide the small bulb up in the hatch somewhere away from anything that could be affected by heat.
 
You'd have to calculate the difference and wire a resistor in with it. That's how my rear turn signals are.
 
Why do you want to have the 3rd brake light flash?

(It's against federal regulations for the 3rd brake light to be illuminated for any reason other than to indicate application of brakes)
 
it does that when you brake. its like a safety thing, flashing lights are easier to see than a light alway on.... i think...
 
DE31 said:
it does that when you brake. its like a safety thing, flashing lights are easier to see than a light alway on.... i think...
Click to expand...

They just really annoy anyone who has to drive behind you. If it was done with a sensor to sense when you are really slamming on the brakes (a la the new Mercedes S-class), then it's useful and not annoying. Luckily I've only had to follow behind someone with a flashing brake light twice, but both times I was annoyed enough to change my route after a few miles of that crap.
 
KanseiZM said:
They just really annoy anyone who has to drive behind you. If it was done with a sensor to sense when you are really slamming on the brakes (a la the new Mercedes S-class), then it's useful and not annoying. Luckily I've only had to follow behind someone with a flashing brake light twice, but both times I was annoyed enough to change my route after a few miles of that crap.
Click to expand...
Thats the purpose..to annoy you..if it is bothering you then you are far less likely to hit that vehicle. This has been used on motorcycles for a long time...and I even pulse my brakes when driving to show when I am braking....you are actually taught this in drivers ed and in defensive driving courses. On a bike I ALWAYS Pulse my brake light,but they do make a tail light inegrator that blinks the brakes for you when applied.
Bottom line is the simple fact that a blinking light draws more attention than a solid one.
 
KanseiZM said:
You'd have to calculate the difference and wire a resistor in with it. That's how my rear turn signals are.
Click to expand...
Bingo..If wiring a regular incandecent bulb in series with the flasher does the trick, then measure the resistance of that bulb and add a resistor in series with a very close value to that of the bulb....Voila! Instant flasher fix.
 
Or use a variable resistor - turn up the resistance until it flashes - then measure the resistance across the variable & buy the nearest resistor.
 
ForceFed said:
Bingo..If wiring a regular incandecent bulb in series with the flasher does the trick, then measure the resistance of that bulb and add a resistor in series with a very close value to that of the bulb....Voila! Instant flasher fix.
Click to expand...

Bulb resistances are typically very low and consequently power consumption tends to be high. If the circuit in question was only designed to provide a small amount of current and you wire in that resistor or bulb and effectively short it to ground it might blow the driver circuitry. Safer I think to put an ammeter in the circuit (the normal circuit, without the flasher) and see how much current is being used. If it's only a few mA then I strongly suggest you find a low current flash circuit and use that instead.

This might also be the case if the wires you are working on go to a relay and not directly to the bulb.
 
OK, I knew I'd get a few questions on the flasher thing.
It only flashes when the brakesa re applied. There are motorcycles and now vans and other vehicles coming out with this feature lately.

It's all about safety! My Miata is lowered and it is black and SMALL! I can't tell you how defensively I have to drive, if you've never driven one in traffic you don't yet understand. I've noticed a MARKED difference in tailgating when I have the flasher in and my 3rd light flashes. It sends a subliminal message, something is different, pay attention, notice the car etc. People literally hang back a bit once I have applied the brakes. Also, at night I want to be SEEN when I slow down.

I could care less that it annoys folks, at least you see me, think about it and maybe get away from me because I am "annoying".

(I do however try to use the e-brake at lights and such as a courtesy when i'm sitting for a bit.)
.............
Anyhow, I think you guys are right about the current thing. I'll have to look at some diagrams and see if there is a relay in there and then test the current. LED's take less power but I thought the same amount of power would be going through the wires. I have an EP-35 flasher and it works on my single bulb application. I'll look for an smaller current one.

I want my wife's P5 to be noticed too.
 
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