issues install flashing module a car 3rd brake light

[wojtek077]

I'm trying to installing a flashing module for my third brake light on my car. I'm having problems with flasher working properly when car's running but when the car is in the on position it works fine. The third brake light goes straight thru a body control module. I tried putting a resistor because as the cars running voltage goes up. I thought the body control module was trying to limit the current. I think problem is that voltage goes to 3v not 0v but the same thing happens when car's in on position. I'm lost now what guys think I should do next?

[KMoffett]

Is this a commercial after market flasher module? Link?

Ken

[wojtek077]

Well kinda of
http://www.3rdbrakeflasher.com/brake-light-flasher-c-65/universal-brake-light-flasherstrober-m1-model-p-181.html

[Audioguru]

A flashing brake light will confuse many old grannies and they will crash into you.

[james_s]

I'm not sure how it could be confusing, I see them all over and they're certainly eye catching. The problem I see is that in the US anyway they are illegal and that means if you do get in an accident it could cause big headaches if an insurance adjuster notices you have it. Their whole job essentially is to find loopholes to weasel out of paying your claim.

[wojtek077]

Flasher saved my butt couple times on my other car. I got rear ended 4 times and blow couple red lights. People suck at driving in my area. Cops actually like the flasher but insurance wise you might have a point.

[Monkeh]

I got rear ended 4 times

One has to wonder about the common factor..

[Gregg]

It seems to me that the car is too smart for the flasher; i.e. the car module that switches the third brake light on when the vehicle is running thinks the there is a problem with the lamp but it bypasses its smart control when the key is off to still allow the third light to work for safety reasons. 
You may have to connect the wiring from the module to a resistor that satisfies the module’s criteria and connect the actual light to a separate (fused) source via a relay; most likely an opto isolated relay to keep any spikes from back feeding the module. 
Another possibility may be to find the output from the actual brake light switch but there is still the same risk of damaging the car’s expensive module. 

If you don’t want to roll your own opto isolated relay, here is a cheap module rated for 30 unrealistic amps but should be fine for your light. https://www.ebay.com/itm/1-Channel-Relay-Module-Board-With-Optocoupler-H-L-Level-Triger-30A-12V-24V/233255072799 The combination high / low trigger allows these modules to easily isolate the LED trigger circuit from the power to the relay coil which can be on the same circuit as the relay output.  They are also available in 10 amp rated, but for the small price increase I would go with the 30 amp rated.

[james_s]

I got rear ended 4 times

One has to wonder about the common factor..

That being what exactly? That people don't pay attention?

I've been rear ended at least 8 times in the last 15 years, most minor, a couple hard enough to damage my car and one totaled it. In every case I was completely stopped either waiting at a red light or stopped in traffic when somebody who wasn't paying attention slammed into my back end. I'd love to know how that's my fault if that's what you're insinuating.

People messing with their mobile phones while driving is an epidemic that now kills as many people as drunk driving. I ride the bus to work now and I see it multiple times every single day, people driving down the freeway looking down at a smartphone in their lap.

[GregDunn]

They are certainly not illegal in the US.  In fact, many dealers will install them as aftermarket accessories when you purchase the car.  There may be specific states which will not pass them during vehicle inspections, however that is a local ordinance.

[james_s]

I was going off of this when I looked into them:
https://www.popularmechanics.com/cars/g1195/10-car-options-the-law-wont-let-you-have/

I notice now it's several years old so maybe things have changed. I do advise consulting the laws in your state though as well as any states you may decide to drive in. I've been very tempted to get one as they do certainly grab my attention but having dealt with insurance adjusters before it makes me nervous.

[wojtek077]

 

If you don’t want to roll your own opto isolated relay, here is a cheap module rated for 30 unrealistic amps but should be fine for your light.

I might do that keep it separate circuit or tap into the taillights. I was thinking doing as last option. Still might think over to either keep flasher you guys valid legal points.

[SparkyFX]

The output to the third brake light might be PWM controlled anyway.

[Brumby]

I'm not sure how it could be confusing,

I tend to agree.  The flashing occurs at the beginning and then stays on.  By the time someone starts actively looking at it, it is likely to be a steady light.  Once they get to consciously realise that it's a brake light, then if it repeats the behaviour, it won't be so much of a surprise.

I see them all over and they're certainly eye catching.

That's the point.  Something that is changing in your field of view will get your attention.  A single change like a light coming on might get missed if you blink - but flashing a few times is much more noticeable.  Unless you notice a change, you might not see the light at all.

A comparison situation is one that has happened to me once or twice whilst driving at night.  I will be driving towards a set of traffic lights that are green and I may have glanced in my rear view mirror, across at another vehicle or some other potential hazard and when my eyes return to the road ahead, the lights have changed to amber in that fraction of a second.  The amber traffic lights then disappear into the field of sodium vapour street lights and become one group.  I then have to realise this before I can react.  This doesn't take long - but it does take time.  SEEING the change from green to amber provides instant understanding.

The problem I see is that in the US anyway they are illegal and that means if you do get in an accident it could cause big headaches if an insurance adjuster notices you have it. Their whole job essentially is to find loopholes to weasel out of paying your claim.

Legal requirements for vehicles, including lighting, are to ensure things perform to a minimum set standard.  To have things certified as doing so requires some hoops to be jumped through and that can take time and money that only a serious local seller would bother doing if they wanted a marketing advantage.  Correct me if I'm wrong - but the onus for legality doesn't lie with the person who sells such after market products, but with those who use it.

One consequence can be that you may have a product that will exceed the required standards - but if it hasn't been granted formal certification, then you could be in for some trouble of one sort or another.  Insurance adjusters are one potential source.

[forrestc]

I'm trying to installing a flashing module for my third brake light on my car. I'm having problems with flasher working properly when car's running but when the car is in the on position it works fine. The third brake light goes straight thru a body control module. I tried putting a resistor because as the cars running voltage goes up. I thought the body control module was trying to limit the current. I think problem is that voltage goes to 3v not 0v but the same thing happens when car's in on position. I'm lost now what guys think I should do next?

Having just dealt with a similar issue with replacing incandescent bulbs with LED's....

Can you clarify what type of bulbs are in use in the third brake light.  What type of car?

If this is a modern car with LED's you might find that this isn't going to work since the body control module may include some LED driver circuitry in it.   

Have you measured across the third brake light when it is powered on (i.e. brake pedal depressed)?   Is it 12V on and 0V off?

[sokoloff]

People messing with their mobile phones while driving is an epidemic that now kills as many people as drunk driving.

That seemed interesting enough to poke for some data, so I went looking.

It seems like distracted driving is about 30% as deadly as drunk driving in the US.

NHTSA estimates 10,874 deaths in US from DUI in 2017
NHTSA estimates 3,166 deaths in US from distracted driving in 2017

[james_s]

People messing with their mobile phones while driving is an epidemic that now kills as many people as drunk driving.

That seemed interesting enough to poke for some data, so I went looking.

It seems like distracted driving is about 30% as deadly as drunk driving in the US.

NHTSA estimates 10,874 deaths in US from DUI in 2017
NHTSA estimates 3,166 deaths in US from distracted driving in 2017

Interesting, now I'm wondering what statistic I saw? Maybe it's the number of accidents rather than the number of deaths? Whatever the case it has reached epidemic levels and continues to increase. I see it every day, I've been the victim of it myself, I know plenty of other people who have been rear ended by someone who was texting or messing with their phone. It's such an easily preventable and entirely unnecessary thing too, just put the damn phone down and drive. If it's such a powerful addiction then put it in the glove box. It's reaching the point where I think it should be illegal to have a mobile phone within reach of the driver just like an open container of alcohol. Causing an accident due to distracted driving ought to be a criminal offense, fine of at least $10k, felony if it injures somebody. Maybe if getting caught messing with your phone while driving means a $600-$1200 ticket people will start to take a hint. I mean I see it myself numerous times every day and it's getting absurd. A while back some guy nearly mowed me down in a crosswalk as he rolled along staring down at the phone in his hand, he passed by about 2 feet away from me as I stared right at him and his eyes never came up until he had passed the crosswalk. I was wishing I had a shopping cart with me, I'd have let it go to roll in front of him.

[wojtek077]

Can you clarify what type of bulbs are in use in the third brake light.  What type of car?

Led 5 I think 2016 Focus st

If this is a modern car with LED's you might find that this isn't going to work since the body control module may include some LED driver circuitry in it.   

Yeah that's problem but some people got it to work tho. In this video he's using the cheaper version of my module the s1. I contacted the seller he said that it's the same module but without the options for adjusting flashing and speed.
https://youtu.be/4CWib_Ncu6Q

Have you measured across the third brake light when it is powered on (i.e. brake pedal depressed)?   Is it 12V on and 0V off?

I think that's the problem goes down to 3v. I think module stays on and doesn't reset because of the 3v. Here's my video of my car
https://youtu.be/Q9VJwAxUtEE

[wojtek077]

The output to the third brake light might be PWM controlled anyway.

Yeah it might be, I just don't have a oscilloscope to test it.

[wojtek077]

 Uber and Lyft I hate to say but helped with drunk driving.  DUI keeps getting  more  and more expansive which is a good thing. I got a feeling that cellphones the next new addition to the DUI. I was driving on the highway one night this girl going 70mph looking at her phone for good few seconds. My friend does road side assistance and his car's straight piped super load so he always goes next to car tell them to put phone down. He will speed up and slow down  so kind he of forces them to put the phone down lol.

[forrestc]

I think that's the problem goes down to 3v. I think module stays on and doesn't reset because of the 3v. Here's my video of my car
https://youtu.be/Q9VJwAxUtEE

You mentioned adding a resistor, where did you add it?  Was it in series or parallel? 

One of my experiences in switching from incandescent to LED's was that the cruise control thought that the brake was always depressed because the LED's weren't pulling enough current to drop the voltage on the brake line down close to zero when the brake pedal was let up.   I think it was also in the 3v range.    It was cured with a load resistor across the 3rd brake light.   I just used the same 6ohm 50W one everyone else uses (and is widely available on amazon).   In your case, you may need to add this between the flasher and the rest of the car, however I'd be a bit concerned if the car came with LED brake lights already that you may end up drawing more than the car is expecting from that line and cause a longer-term fault.

Another option would be to add a couple of 1N4001 or similar silicon diodes in series to try to drop a bit of the voltage.   Each one should drop around 1 Volt.   However this might affect the brightness of the brake light depending on the driver circuit in the light itself.   

[wojtek077]

You mentioned adding a resistor, where did you add it?  Was it in series or parallel? 

Yeah I added a 33ohms 1/2w resistor before the flasher and the led.

you may end up drawing more than the car is expecting from that line and cause a longer-term fault.

I seen on back of led light saying  0.8w at 13.5v but drowning only 0.6w at 13.7v with a flasher too. I think I'm still good.

Another option would be to add a couple of 1N4001 or similar silicon diodes in series to try to drop a bit of the voltage.   Each one should drop around 1 Volt.   However this might affect the brightness of the brake light depending on the driver circuit in the light itself.   

I tried to add one 1n4001 but it same thing. I add them on positive side tho

[james_s]

Uber and Lyft I hate to say but helped with drunk driving.  DUI keeps getting  more  and more expansive which is a good thing. I got a feeling that cellphones the next new addition to the DUI. I was driving on the highway one night this girl going 70mph looking at her phone for good few seconds. My friend does road side assistance and his car's straight piped super load so he always goes next to car tell them to put phone down. He will speed up and slow down  so kind he of forces them to put the phone down lol.

If I had a big ugly truck I'd be seriously tempted to pull a normally safe distance in front of them and brake aggressively. I'm not a fan of the typical approach to fighting drunk driving which is to just reduce the breath alcohol threshold that is considered drunk. I think that probably makes it worse, I mean if you're gonna get a DUI after one beer if you get caught anyway you might as well have a few more drinks, not gonna get in any more trouble. Instead I think they need to aggressively go after people who are heavily intoxicated and more so repeat offenders.

A while back somebody around here drove right into the back of a DOT incident response truck that had flashing lights on, they were of course glued to their phone and didn't even look. Heck maybe if we stopped trying to make cars so safe it wouldn't encourage idiots to breed.

[wojtek077]

Yeah I agree, I don't even want a beer if I'm driving. People drive piss drunk and don't care. I keep road to a min tho you never know what people can do. And also have dashcam just in case.

[forrestc]

I seen on back of led light saying  0.8w at 13.5v but drowning only 0.6w at 13.7v with a flasher too. I think I'm still good

My suggestion was to draw around 25W on the brake light circuit to force the voltage when off to drop to zero.  i.e. put a 6ohm resistor in parallel with the entire thing.   

If the existing one is only drawing 1W this would be too much.   

You could also try a 3.3V zener backwards so that it adds 3.3V of drop.

Edit/Addition:   It also occured to me just after I posted this reply that there are circuits out there which will cut off below a certain voltage.  Usually they're used to prevent overdischarging a rechargeable battery or prevent something from running at too low of a voltage.   If you google 'low voltage cut off circuit' or 'low voltage disconnect circuit' you'll probably find a few.