Automotive Brake light "Interrupt" module/relay when turn signals are on?

och

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I have a motorcycle tail lamp that uses the same bulb for brake and turn signals. When the brakes are applied, constant power is being carried to the bulb through the brake light power wire, and when a turn signal is on, "intermittent" power is being carried to the bulb through the turn signal power wire. The problem is when the brake and a turn signal are on at the same time, I need a relay that will interrupt the constant brake power to the side where the turn signal is on, so the bulb can flash.

Most older American cars were setup this way, so I imagine a relay that does what I am looking for should be readily available. Can someone point me in the right direction please?
 

-Virgil-

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This sounds like you started out with a single, central stop-tail light and separate left/right turn signals, and now you want to change it so you have left and right stop/turn lights. If you care about you and your bike staying in one piece with all the parts working as designed, you would want to take another think about (not) doing this. Compared to a setup with red rear turn signals of either the separate or combined type, you are significantly less likely to get hit in traffic if you have separate amber rear turn signals, plus the separate red stop light(s).

Before the era of body control modules and multiplexed/CANbus controls, combination stop/turn lights were driven by a specifically-configured turn signal switch which feeds power from the stop light switch to both lamps when the turn signal is not in use; power from the turn signal flasher to one or the other lamp when the turn signal is in use (plus power from the stop light switch to the other-side lamp, if the brakes are in use); and power from the hazard flasher to both lamps when the hazard flashers are in use. Without that kind of switch, you could cobble up a trailer converter to do (sort of, halfway) what you want, while creating other operational problems and not being very reliable.
 

och

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This sounds like you started out with a single, central stop-tail light and separate left/right turn signals, and now you want to change it so you have left and right stop/turn lights. If you care about you and your bike staying in one piece with all the parts working as designed, you would want to take another think about (not) doing this. Compared to a setup with red rear turn signals of either the separate or combined type, you are significantly less likely to get hit in traffic if you have separate amber rear turn signals, plus the separate red stop light(s).

Before the era of body control modules and multiplexed/CANbus controls, combination stop/turn lights were driven by a specifically-configured turn signal switch which feeds power from the stop light switch to both lamps when the turn signal is not in use; power from the turn signal flasher to one or the other lamp when the turn signal is in use (plus power from the stop light switch to the other-side lamp, if the brakes are in use); and power from the hazard flasher to both lamps when the hazard flashers are in use. Without that kind of switch, you could cobble up a trailer converter to do (sort of, halfway) what you want, while creating other operational problems and not being very reliable.

Ah, no, it is actually far more complicated than that. I have a Harley trunk with a Harley lamp on a non Harley motorcycle. On a Harley, the computer handles the operation of the lamp, but on my Yamaha I have to make it work myself.

In a nutshell, it is a LED lamp with five wires - ground, running light, brake light, left signal, and right signal.

The running light is a dedicated set of LEDs, but brake and turn signals share the same set of LEDs. The way it operates is akin to what you're describing in older cars without BCM/CANBUS.

The ground and running light are self explanatory and static. Applying power to left/right turn signals individually turns on the respective side with the sequential effect, and applying power to both turns on both with the sequential effect.

Applying power to the brake light wire by itself doesn't do anything. However, applying power to the brake and both turn signal wires turns on the whole lamp without the sequential effect, just like the brake is supposed to function. Also, applying power to the brake wire and just one of the turn signal wires turns on the respective side without the sequential effect, allowing the other side to function as turn signal.

I need to to function as brake and turn signal, so I need to figure out a module to interrupt constant brake power from going to the side where turn signal is on, and instead take the "flashing" power.

This is a video I made to visualize what is going on.

 

-Virgil-

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Oh! Well, it strikes me Stern's DRL-1 module could probably do the job. It's basically an automatic A/B switch which feeds the outputs (left + right lamps) according to what it sees on two inputs. In addition to creating combination DRL/turn lights from front turn signals, it's been applied to create combination stop/rear fog lights, and to create combination turn signal repeater/side marker lights as shown here. If I'm understanding you correctly, the task you have in mind is basically the same thing.

If I've gotten it wrong (haven't understood you correctly), then -- stab in the dark -- maybe this could be put to work doing what you want.
 

-Virgil-

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Similar to what you posted, but your products interrupt running light, I need to interrupt brake light.
The module doesn't know brake lights from "running" lights, it knows inputs and outputs. The installer (that's you) gets to decide which is the priority input, and which is the interruptible input. Those trailer converters you linked are the hokey-aѕѕ junk I was warning about, above.
 

och

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The module doesn't know brake lights from "running" lights, it knows inputs and outputs. The installer (that's you) gets to decide which is the priority input, and which is the interruptible input. Those trailer converters you linked are the hokey-aѕѕ junk I was warning about, above.

Thank you! I will cancel the order for the trailer converter then.

With the first module you've posted, I understand that it shouldn't know brake light from running light, but normally running lights, at least in the rear, operate at lower amperage - can this become a problem?
 

-Virgil-

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You're running LEDs; overload current on the module is probably not going to be on the list of worries.
 
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och

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You're running LEDs; overload current on the module is probably not going to be on the list of worries.
Also, any chance you can briefly explain the difference between the trailer conversion modules I posted, and the DRL-1 module from your link?
 

och

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Welp, received the cheap trailer converter, and it doesn't work at all. https://www.amazon.com/dp/B001EP0GI6/?tag=cpf0b6-20

Maybe its defective, but it doesn't output any voltage no matter what, this is the circuit inside.

RvoUYB2.jpg
 

turbodog

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-Virgil-

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The various modes might be selectable as you want, but those turn signals are not working appropriately. There is far too little full-on time...matter of fact, there's almost none. Whatever you and/or this bike is using to create the on/off power for the turn signals (in the old days it would be a turn signal flasher, sometimes it still is) is not a good match for this lamp. You need one that will have a longer "on" time, essentially a slower flash rate with a longer duty cycle.
 

och

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The various modes might be selectable as you want, but those turn signals are not working appropriately. There is far too little full-on time...matter of fact, there's almost none. Whatever you and/or this bike is using to create the on/off power for the turn signals (in the old days it would be a turn signal flasher, sometimes it still is) is not a good match for this lamp. You need one that will have a longer "on" time, essentially a slower flash rate with a longer duty cycle.

It may seem this way because I was flipping the turn signal switch left to right way too quickly, but either way, the flash timing is purely a function of the flasher module in the bike. There are flasher modules that allow you to adjust timing, but I'm kind of happy with it the way it is. Here is the final result.

 

-Virgil-

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You might like it, but, all due respect, that's not what matters; it's really not right. There really needs to be some definite duration to the fully-lit condition.
 

och

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You might like it, but, all due respect, that's not what matters; it's really not right. There really needs to be some definite duration to the fully-lit condition.

It's an easy fix, I'll consider getting a programmable LED flasher, but from what I see on all bikes and cars equipped with sequential signals, they all shut off immediately once the sequence reaches up the last LED.
 

-Virgil-

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There is no shortage of crappy motorcycle lighting on the North American continent...much of it aftermarket, but still a large amount of it as original equipment.

The cars with legitimate/legal sequential turn signals have some full-on time at the end of each sequence, except for some Audis where there's an on-off turn signal serving the legal requirement, plus a sequential strip serving as a toy.
 
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