Brake light flasher

[jdub]

I installed a Denali B6 third brake light along the bottom edge of the license plate and it is quite bright, easily overpowering the stock brake light. At the same time, I tried to install a brake light flasher but could not get it to work. I've installed the same make/model of flasher in two other bikes and they work great.

The flasher worked fine when I tested it and the B6 on the bench, but I can't get the flasher to work on my '15 Norge. I think it is because the brake wire (yellow/green) has 7 volts even when the brake is not activated. Both the stock brake light and the B6 go to full brightness when the brake is activated, but the only time there is any flashing is when the ignition is first turned on. Even then, the flashing (at both lights) is at a rather dim level. What is weird to me is that the stock brake light flashes as well during the ignition key-on. Somehow, the flasher is able to make the stock brake light flash despite a constant 12 volt feed to that light when the brake is activated. The flasher simply taps into the 12 volt feed but I don't see how it can alter that feed.

I am willing to try a different flasher if anyone has had success with it. On the other hand, if the presence of 7 volts in the brake wire when the brake is not activated is abnormal, I will need to do some more troubleshooting. Any suggestions?

 

[kiwi dave]

The 7 volts will be just leakage through the brake light LEDs, meaningless when you are measuring it with a high impedance voltmeter. I would just ignore this measurement.

I am not familiar with the Denali B6, and unaware how you are connecting it in the bike's wiring. I assume a lead from the B6 is being connected to the parallel combination of the front and rear brake switch, but where are you connecting the other end?

Perhaps you could try adding a diode to the connection from the B6 to the front and rear brake switches, to see if this solves the problem.

Edit: I've found the B6 wiring set up. Place the diode between the orange wire and where the front and rear brake switches connect to the LED brake lights. The direction of the diode should be anode to the B6, cathode to the brake switches/LED stop light junction.

 

[jdub]

Thanks, Kiwi. I know nothing about diodes. Would you be so kind as to send me a link for one? Additional notes and observations are below. Hopefully, the diode will address these issues.

I should have mentioned earlier that the flash unit only flashes for a couple of seconds, then goes solid for as long as you hold down the brake. When you release the brake, the flash unit resets and will be ready to flash the next time you apply the brakes. I think the 7 volt "standby" voltage is preventing the flasher from resetting, and might also explain the weak flashing upon key-on.

What I can't understand is why the stock brake light flashes (at key-on). The flash unit has three wires: ground, the 'in' from the brake wire, and the 'out' to the B6 (orange wire). The 'in' is a posi-tap to the yellow/green wire at the taillight connector near the back of the tailsection. Yellow/Green shows 12V when the brake is applied, and 7V when the brake is released. The 'out' goes to the B6 orange wire. So with nothing 'inputting' to the stock wiring, and no stock wires being bypassed or cut, why is the stock brake light flashing?

The ground wires for both the flash unit and the B6 are connected to a fuse block I installed. I later tried moving both ground wires to tap into the factory blue wire on the taillight harness but it made no difference.

There is a third wire (red) on the B6 for running light. I had that connected to a switched positive lead that is not part of the brake light wiring (it was getting a little crowded in that area), but I later tapped the B6 red wire to the yellow/grey wire on the taillight harness and saw no difference.

I also tried switching the flash unit's 'in' and 'out' wires - it made no difference. Both the Norge brake light and the B6 would go bright when the brake was applied, and go dim when the brake was released - the same as before the wiring reversal.

I also noticed the B6 red wire (running light) could be disconnected and it would still light up even when the brake was not applied. Connecting the red wire would make the B6 running mode slightly brighter, and might even be preferable (to leave red disconnected) since it increases the contrast between the brake mode and running mode. In other words, connecting the red wire might be bright enough that drivers might think you were riding with the brakes on. With just the orange (brake) and black (ground) wires of the B6 connected, the running mode is slightly dimmer.

 

[jdub]

The B6 makes the stock taillight seem like it's not working! If I could get the B6 to flash, it would be very attention-getting!

 

[kiwi dave]

The B6 red wire should be connected to the yellow/grey wire, this is the circuit that supplies the tail light on the Norge. You must connect this as it also provides switched power for the Denali B6 unit itself.

The orange wire should be connected to the brake switches/LED stop light junction as I mentioned above.

Also make sure the black wire has a good ground connection.

If it still doesn't work, then try the diode as suggested. Buy one from Radio Shack for a few cents, probably a 100 mA one will be fine. As the sales person to identify the anode and cathode for you (or someone else in the shop if the sales person is clueless).

 

[kiwi dave]

I might add that a brighter tailight/brake light is not necessarily "better" from other road users point of view. If it is so bright it dazzles the person behind you, he/she might just proceed forward temporarily blinded hoping that their vision will "clear" once you take your brake off. Not defending this action, but it is something to be aware of.

 

[jdub]

I ordered a Zener diode variety pack. If I can keep the 7V standby voltage from reaching the flash unit, I think it will work. I tested key-on while holding down the brake and the flashing was very bright - not the dim flash when there is only 7 volts in the brake wiring.

 

[jdub]

Well, I got the third brake light to flash...briefly. My goal was to wire the diode in reverse to keep the 7 volt standby voltage in the brake wiring from reaching the brake light flasher, but still allow 12 volts to pass when the brake is applied. I tried 12 volt, 10 volt and 7volt diodes but they all prevented the brake light in the B6 from coming on. The 4.7 volt diode worked, at least in the garage.

However, by the time I got to work the B6 would no longer go into brake mode, either steady or flash. The running mode still works but that is a separate wire that is not connected to the diode. I might as well try another diode value that came in the assortment pack. But the Zener diodes I bought are tiny. They are only rated at 0.5 watt so perhaps it broke or burned out. If so, I may try a 5 watt diode.

 

[kiwi dave]

I reckon you're playing with fire. A little knowledge is a dangerous thing.

Have you actually wired it as the manufacturer stipulates? If you have and it's doesn't work, you've probably shagged it.

 

[jdub]

I'll check it out when I get home, but I doubt anything got hurt except possibly a fried diode.

 

[jdub]

After bypassing the diode the B6 works fine. I will try a larger 5 watt diode to see if I can get the flasher to work for more than a few minutes. If it doesn't work, I'm giving up on the flasher and will just live with a non-flashing third brake light.

Has anyone else tried a flasher that works? Or for that matter, noticed a standby voltage in the brake line even when the brake is not applied?

 

[NJNorge]

I'm having a similar issue with my 2015 Norge...never thought to measure the voltage in the brake line after releasing the brakes.

I’m using a "Universal Flasherz" unit from Radiantz. Since I'm not big on splicing into factory wiring, I made a “plug and play” harness for it…picture is below.

I plugged everything in and set the box to strobe/solid/repeat. When I turn the key on, the running light comes on like it’s supposed to. When I pull the brake lever, it strobes 3 times, goes solid, and after a few seconds, repeats like it’s supposed to. When I let go of the brake, it goes back to running light, but every few seconds the running light strobes three times. It keeps doing that until I turn the key off. Same thing happens when I set it to blink/solid/repeat.

If it set it to blink/solid or strobe solid, it does what it’s supposed to do once and then works like a regular brake light (no strobe or blink) until I turn the key off and back on. It’s as if the flasher box doesn’t recognize that I let go of the brake lever…the presence of the standby voltage you measured makes that make sense. Question is what to do about it....

 

[jdub]

Nice work with the harness. I gave up on trying to get a flashing brake light with my Norge. I tried several diodes and I don't think that is the answer. A "little" diode worked for a little while (less than one hour) but burned out. I tried two "bigger" diodes and neither one let enough voltage through to trigger a brake flash. I might have gotten lucky if I kept trying different diodes but I noticed the ones that didn't work were hot to the touch after just a few seconds. It wasn't worth the risk so I gave up on the idea of having a flashing brake light, and removed the flasher altogether.

Perhaps a more electrically savvy person can think of a solution or has figured it out.