Tail Light Warning Light...What's The Fix?

[86er]

I just installed LED taillights and now I'm getting the warning light on the monitor. If I leave one incandescent bulb in, it doesn't trip the computer, but it doesn't look as good either. I know that somebody around here knows the fix other than black tape over the red warning light! (I fixed the battery warning light that way until I could get around to adding the resistor!) So, what's the fix?

 

The LEDs that I used have a ring of lights around the base to hit the reflector. They don't reflect as much as a regular bulb but they are brighter anyway.

 

I will probably go with the turn signals when I can afford them. The question is: Will I run into this again with the reduced load on the turn signal system?

 

I didn't find anything about the warning light in the [ame=http://www.venturerider.org/forum/showthread.php?t=9477]LED Tail Light[/ame] thread

 

 

 

 

[bongobobny]

Well, bubba, you may want to try spraying an incadescent bulb black and let it dangle, or add an incadescent brake light somewhere else. As far as the turn signals, the flasher will flash really fast with the LED bulbs, or won't flash at all. You will need to install one of those "Shunt" resistors available for LED conversions on turn signals. A resistor may also fix your indicator light as well...

 

 

Just don't let the smoke out whatever you do...

[GeorgeS]

The current draw of the led's, is much lower then standard bulbs.

 

I have same problem on my 89. However I added 9 very small marker bulbs in the Reflectors around the bags, and between the turn signals ( the reflector) That upped the current draw. But the warning still comes on when engine idleing.

 

Adding an extra bulb in the tail light would do it. Or add a resistor in parallel with the LED bulbs. ( measure resistance of a standard bulb ) and use that amount of resistance.

 

Or, you could add two extra tail lights on the rear, powered from the same Tail light circuit.

[86er]

One of the main reasons that I am going to LEDs is to reduce the load on the system (read: Stator!) but if I add resistance with another light or even a resistor, aren't I just going back to square one?!? Is there any other way to fool the computer?

 

 

[GeorgeS]

But you have to get into the CMS ( computer monitoring unit ) and do some modifications.

 

Trying to remember who posted as how to do that, ??? can't remember.

 

Something about bypassing one component on the circuit board. You have to remove the Instrument panel, and open it up. Pull out the boards and do the soldering job.

 

I'm thinking " skydoc " might be the guy who made that posting.

 

Have you installed the aftermarket Stator ? That would also solve the current draw problems.

[SaltyDog]

You can add jumpers to the CMS board and bypass the reed switches in the load coils for the warning display. It is probably a good idea to resolder the plug connections to the board to prevent future problems anyway. I posted a picture showing the layout of the CMS boards before with the directions when I went all LED on my '83 Standard Venture. You can read the post here [ame=http://www.venturerider.org/forum/showthread.php?t=33285]Pinout of the "information display" on the dash - VentureRider.Org[/ame].

 

I have more pictures of the board if you need them. NOT for the faint hearted, but not that difficult.

[SaltyDog]

Here are a couple of views (front and back) of the CMS board with the load coils and reed switched inside them. I also have a hand written layout of the CMS plug showing the pin functions of the wires going into and out of the CMS assembly.

 

I added jumper wires to the back of the board and bypassed the reed switches so the lighting current through the load coils have no effect on the warning display. Since the LED lights are virtually a lifetime proposition, I don't really need to monitor the health of the lighting circuits. I will bypass my headlights (high and low) at a later date when I go the HID route with the headlight.

[frankd]

86er,

 

Reducing the load on your electrical system is great, except it doesn't lower the draw on the stator one bit. The stator is around a permanent magnet rotor. That means because the magnetic field never changes, the only thing that changes stator output is a change in engine speed. The faster the engine spins, the more the stator puts out. The voltage regulator contains a shunt regulator. When the voltage reaches about 14.5 volts, the shunt regulator starts to conduct, dissipating any extra energy as heat. Another way to look at this is to have a faucet on the output of a water pump, and regulating the output pressure by adjusting the faucet. The more you open the faucet the more water escapes, which lowers the sytem pressure.

 

What this all means is that when you're going down the road with your new low current tail lights, your voltage regulator will let a little more energy go to to ground, and make a little more heat.

 

Frank D.

[rhncue]

86er,

 

Reducing the load on your electrical system is great, except it doesn't lower the draw on the stator one bit. The stator is around a permanent magnet rotor. That means because the magnetic field never changes, the only thing that changes stator output is a change in engine speed. The faster the engine spins, the more the stator puts out. The voltage regulator contains a shunt regulator. When the voltage reaches about 14.5 volts, the shunt regulator starts to conduct, dissipating any extra energy as heat. Another way to look at this is to have a faucet on the output of a water pump, and regulating the output pressure by adjusting the faucet. The more you open the faucet the more water escapes, which lowers the sytem pressure.

 

What this all means is that when you're going down the road with your new low current tail lights, your voltage regulator will let a little more energy go to to ground, and make a little more heat.

 

Frank D.

 

This is all absolutely true but the problem is that the system barely puts out enough energy to sustain the requirements of the bike itself. Add a few extra lights or other things that use energy and the system cannot keep up. I have two rear bumpers that had 18 conventional lights with 2 bulbs each and when I would use the two driving lights up front, I would have to turn the bumper lights off or the battery starts discharging as I drive. A couple of weeks ago I changed all of the running lights on the bumpers to LEDs and now I can use them and the driving lights at the same time. I wish there were a lot of other items I could change so easily to get more juice so that I could add more toys such as more lights, heated gloves or maybe vest, GPS and such.

 

Dick

[a1bummer]

We just want to, "Rob Peter to pay Paul", as my Dad & Grandma always put it.

[a1bummer]

After reading this thread I decided to dig into the display of my 84. I knew right away that the display would be different than the 83's covered previously in this thread. I found two much more complicated PC boards. But as with the 83, my 84 also had the same reed switches. I'm guessing that the 84-93 displays are the same. Please correct me if I'm wrong. I attached a few pictures of the 84's display innards and the reed switches that need to be jumped. One picture shows where to solder the jumpers. The green jumper is for the running/tail lights and the black jumper is for the brake light. Now I no longer have the annoying red warning light. I also didn't have to add any of those expensive resistors that the manufactures of the LED lights suggest adding inline to each LED light.

 

Thanks for the previous information provided earlier in this thread that showed me where to start this LED fix on my 84.

Edited March 1, 2010 by a1bummer

[Squidley]

Todd,

Sounds to me like you need to install a load equalizer for that circut. I know that some have put LED's in their turn signals and they flashed short and fast. The load equalizer levels out the system as far as I understand the unit.

[86er]

This is all great info! I like the idea of fixing the board and the reed switches. I've already been in there once for the "obligatory" re-solder, so that doesn't scare me too much! I just may use the "Black Tape Cure" until I need to take the fairing apart again.

 

I think, Brad, that a load equalizer is just a bunch of resistors to balance out the lighter load of the LEDs. Again, we're back at square one, although when I do the turn signals, I will probably do that.