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I confirmed on my 2007 F800 ST that a 100 ohm resistor 2W or larger solves the LAMP errors. Then any LED bulb with the correct base will work for tail brake or turn.

You need a resistor for each bulb in parallel.
Q; do I need a resistor for the tail light and another for the brake, or can I put one resistor on the ground wire?

Also; I'm in Milw too; near Mayfair.
 

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Yes, one on each. But I would use a mount-able resistor thermally bonded to the frame to help dissipate the heat on the tail light wire because it is always on and the resistor will get HOT if it can't cool. I still have not done the tail/brake light yet.
 

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I’m resurrecting this post since I find it’s the best match for my comment.

A research in old posts did reveal severals ones revolving around LED replacement options for our generally weak brake light.
Quality LED bulb should provide more light output but would most likely trigger a Canbus light error.
I haven’t found a single post on the most simple solution to replace the 5/21w bulb with a brighter halogen bulb.

I just replaced mine with a standard 1157 (Bay15d socket) halogen bulb with a 15/55w output! And what a difference!
Is this such a stupid idea the reason why I can’t find any post on this obvious easy solution?
I know halogen runs hotter than regular bulb but I don’t think 15w will be hot enough to melt the reflector. And the 55w will only be ON for cycles of a couple of minutes. I Will keep a close eye just to make sure nothing is melting but I don’t expect it will.

Anyone had tried this before?
 

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.........I haven't found a single post on the most simple solution to replace the 5/21w bulb with a brighter halogen bulb.

I just replaced mine with a standard 1157 (Bay15d socket) halogen bulb with a 15/55w output! And what a difference!.......
Not tried this on an F800 but have swapped a bulb out on a bike that had separate tail and stop light bulbs. The tail light I changed from 5W to 10W the stop light I kept the same 21W. It is not actually legal in the UK but I didn't have any problems with the police. Older bike with no intelligence to know if bulb was correct, bust or over watted.

I was not actually aware that a dual filament 15/55W bulb existed, surprised it does not trip an error as it's way over the stock wattage. Only issue I could see is that stock wiring is meant to carry only just over 400mA for tail light and 1.75A stop light, those go up to 1.25A and 4.6A sizable increases, might be worth having a look at what the minimum wire gauge requirements are for those increased currents see if stock wiring is close.

For what it's worth I added two LED tail stop lamps to the rear of my GT as felt it could do with a little more light back there. I have them wired as tail/fog lamps.
 

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I didn't replace my taillight bulb, but I added a 9W LED bar as a 3rd/additional brake light.
It's P-STRB-1R18: Red from superbrightleds.com.
I made a bracket from an old car lisc. plate and mounted it above the bike lisc. plate.
I also used a smart flasher that blinks it real fast 5 times when it comes on.
No Lamp error.
 

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I was not actually aware that a dual filament 15/55W bulb existed, surprised it does not trip an error as it's way over the stock wattage. Only issue I could see is that stock wiring is meant to carry only just over 400mA for tail light and 1.75A stop light, those go up to 1.25A and 4.6A sizable increases, might be worth having a look at what the minimum wire gauge requirements are for those increased currents see if stock wiring is close.
Thank you for pointing this out! I didn't considered this aspect. After looking around I found in my Haynes manual that brake light wire used on f800 are .5 square mm cross sectional diameter. So this translate to 20 gauge (AWG). From there I was able to find sources that states that 20 gauge wire can sustain 5 amp on 4.5 feet long circuit. That is IF the wire is a single open air cooled wire which is not the case here. The sources consulted suggest to lower amperage capacity by 40% for a 5-6 wire loom bundle together.
So I might end up with a burned out wire using a 55 watt bulb [:(]. Ok then... time for plan B I guess.
 

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I didn't replace my taillight bulb, but I added a 9W LED bar as a 3rd/additional brake light.
It's P-STRB-1R18: Red from superbrightleds.com.
I made a bracket from an old car lisc. plate and mounted it above the bike lisc. plate.
I also used a smart flasher that blinks it real fast 5 times when it comes on.
No Lamp error.
Thanks for the suggestion. I might prefer this route as opposed to changing to a led bulb considering I have a top case mounting frame to secure it to.
 

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Hello, I appreciate that this is an oldish thread but led tech seems to be advancing at a pace and the question still seems to be unanswered.

I am in the process of trying various plug and play tail/brake leds and will report back.

In the meantime I looked up the accepted current draw for a 0.5mm loom wire which seems to be 11 amps according to Mr google. By this reckoning 5A should be fine!
 

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So another supposedly 'CANbus' error free bulb tried. So far that's 3. 1 did work but the light output was low. The other two were really bright just with the tail light on, then when the brake was applied the LAMP light came on on the dash and switched off the circuit.

Does anyone know why this is happening? Is the load too much perhaps? The dimmer one was fine for no errors, but lousy as a light source. I don't really know what I'm looking for now, or how to find it.....
 

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Found one!!!!

So got leds across the whole bike now. No errors and all much better than OEM for brightness!

 
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