Headlight modulator

[Jeff Pattee]

Does anyone else run a modulator on their high-beam? If so, does your white override dash light modulate with it at times??

[crazy steve]

I would expect it would... that light is the indicator for a burned-out lamp and the reserve lighting unit that operates it 'checks' by measuring the lamp load; change the load, and the RLU will think the light is malfunctioning.

[Jeff Pattee]

modulator

Yes, I knew that the unit checked the current flow to the low-beam....was kinda surprised that it worked in reverse........ie The modulator only works in the daylight on high-beam. But then again, the idiot light is there to tell u that your headlight is burnt out so it must read all of the volts going thru regardless of which beam u have on......k, think I got it now

[crazy steve]

The RLU checks both lamp filaments; it's designed to switch on the other half of the light if either fail, not just the low beam. If the low beam fails, it switches to high but reduces voltage to the lamp so you don't blind oncoming traffic. If the high fails, it just switches to low.

So that makes me wonder... does the light actually 'modulate', or are you really seeing an interaction between the modulator and the RLU? If the high beam 'fails', the RLU switches to low beam and lights that indicator lamp.

This might 'wear out' the RLU over the long haul, but I can't say for sure...

[CatatonicBug]

If the high fails, it just switches to low.

Not true... The RLU only senses the low beam, and will turn on the high beam at a decreased wattage while turning on the idiot light. If you switch to the high beam with a dead high beam filament, the RLU does nothing, and the idiot light does not come on.

I personally have seen, and heard a few others mention that the idiot light actually stays on very dimly lit even when the low beam is still good. Only noticable on a dark road at night, but it's there.

[crazy steve]

Not true... The RLU only senses the low beam, and will turn on the high beam at a decreased wattage while turning on the idiot light. If you switch to the high beam with a dead high beam filament, the RLU does nothing, and the idiot light does not come on..

Sorry 'Bug, it is true. It does check both (look at your FSM), so if yours is doing that, it's only half working....

[CatatonicBug]

Well, I tested it before I upgraded to the HID light, to test this very idea and it worked as I described. I had a dead low filament, and if I hooked it up to "trick" the system into thinking it was the high beam filament, the idiot light did not turn on. It simply did not turn the dead filament. However, if connected "correctly", the high beam came on at a reduced wattage and the idiot light came on.

[DGXSER]

Jeff, I have installed one of those modulators on my bike, but I removed the RLU before I installed it (when I installed an HID lamp, since removed as I found it really did blind oncoming traffic.). Easy solution if it bothers you, remove the RLU.

[Jeff Pattee]

modulator

It doesn't really bother me. I had read a post the other day about someone who had found out that his high and low beams had the wires transposed, and since my light was coming on when I had it on high beam, I thought that maybe that was happening to me......Just thought I would post the question before I had to go to the hassle of trying to put my headlight back together with all the other modulator stuff crammed in there.....but it looks like I should do it anyway.....just to make sure.......ahhhhhh....life with an xs....

[Jeff Pattee]

modulator

BTW I am running an off road bulb.