High beam indicator problem using LED headlights (Solved)

RooK

Supercharged
Joined
Nov 18, 2006
Messages
315
Location
Devon, Alberta, Canada
Ride
'06 RIII
For those having the issue of the high beam indicator staying lit after fitting LED headlights

What happens is there is voltage leakage of one (or both) headlamps sending power back into the high beam wiring from the headlamps. The problem seem to be worse as the headlamps warm up.

When cold mine had a 1.2V then as it warms up it is sending up to 5V. At some point in there there is enough voltage to keep the high beam indicator on.

FIX 1: you can install an isolation relay

FIX 2: Used a 2.8K Ohm 0.25w resistor between the high beam (Blue/White) and and neutral (Black) right behind one headlamp.

The resistor will "burn" the excess power and the high beam indicator won't turn on as it will keep the voltage around 0.2V dissipating 0.001W on low beams.

Anything over 1000 Ohm will work fie for a 1/4Watt resistor, below 1K Ohm would work too but keep in mind it will need to a higher wattage for when the high beams are used. Roughly 1K @ 13.7V will dissipate 0.2 Watts

Since both headlights are in parallel, this need to be done only at one light.

I hope this helps!
 
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Rook, you are the Man! I just did the "resistor" mod and all I can say is "you the Man!! This is why I'm digging the R3Owners Forum!! After I installed those LED'S that darn light came on, WTF? Could not figure out why. Did the install, took it for a 30 mile test ride ( that's when it would rear it's ugly head) and no light on!! . Now, the test is this weekend for a 400 mile round trip with the misses!
 
As mentioned in another thread, One could instead put a 5A diode on the high beam lead.
That would need to be done on both sides, would cost more and there will be a slight voltage drop (0.3V - 0.6V) on high beams only.

Technically the diode is the right thing to do. But since the leakage is from cheap components the resistor fixes the issue.
 
This is a fine example of how good information can be shared in forums. I just purchased a 2006 a few days ago and swapped out the headlights for LED Projection lights and had my highbeam indicator on all the time. No more. Thanks Rook for the post.
 
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