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While playing around with two 55watt driving lights as a replacement for my stock headlight I discovered something interesting.
If I simply plug each driving light into the stock headlight plug (3 spade plug) with green being low beam, yellow being high beam, and black being ground. One driving light comes on for “Low Beam” and the other comes on (low beam goes out) for “High Beam”. No surprise. They both even had the dim glow typical of the XS headlight with engine off or idling.
What I wanted was one driving light to be on when in “Low Beam” and both on in “High Beam. I picked up a couple of 30am Aux. Light relays from the local “Auto Zone” and proceeded to wire them in. After several failed attempts to get the lights to work the way I wanted, I realized that the “Reserve Lighting Unit” (RLU) was getting in the way.
As a last configuration, I wired each relay to drive each light, with 12v coming from the battery. Actually there is a red wire in my headlight bucket that does not go anywhere and is switched on/off with the key, so I used that.
To my surprise, the driving lights worked the way I wanted; one light on for “Low Beam” and two lights on for “High Beam”. Again, I can only image that the RLU has something to do with this. Just as significant is, that in either mode, the lights where bright even with the motor off.
I reinstalled the stock headlight without the relays and observed the normal response to the Low/High beam with the motor off. Dim on low beam and even dimmer on high beam. I also observed that only one element in the stock H3 bulb is on at a time.
When I reconnected the relays with the stock headlight it was bright for “Low Beam” and very bright for “High Beam” (both elements on), with the engine off. I don’t have any way of measuring actual current draw, but it looks to me like the RLU pulls more power (watts) to run the headlight than is needed.
The down side is now the RLU is effectively out of the picture, so if one of my elements where to go out, I would not know it or have a headlight. For me, more light for less is more important than the RLU.
What I also don’t know is if what I have discovered is unique to my XS or typical for all XSs. Anybody else tried this?
FYI: To get the headlight on with the engine off, I start the bike to get the headlight to come on and then use the kill switch to turn off the motor.
If I simply plug each driving light into the stock headlight plug (3 spade plug) with green being low beam, yellow being high beam, and black being ground. One driving light comes on for “Low Beam” and the other comes on (low beam goes out) for “High Beam”. No surprise. They both even had the dim glow typical of the XS headlight with engine off or idling.
What I wanted was one driving light to be on when in “Low Beam” and both on in “High Beam. I picked up a couple of 30am Aux. Light relays from the local “Auto Zone” and proceeded to wire them in. After several failed attempts to get the lights to work the way I wanted, I realized that the “Reserve Lighting Unit” (RLU) was getting in the way.
As a last configuration, I wired each relay to drive each light, with 12v coming from the battery. Actually there is a red wire in my headlight bucket that does not go anywhere and is switched on/off with the key, so I used that.
To my surprise, the driving lights worked the way I wanted; one light on for “Low Beam” and two lights on for “High Beam”. Again, I can only image that the RLU has something to do with this. Just as significant is, that in either mode, the lights where bright even with the motor off.
I reinstalled the stock headlight without the relays and observed the normal response to the Low/High beam with the motor off. Dim on low beam and even dimmer on high beam. I also observed that only one element in the stock H3 bulb is on at a time.
When I reconnected the relays with the stock headlight it was bright for “Low Beam” and very bright for “High Beam” (both elements on), with the engine off. I don’t have any way of measuring actual current draw, but it looks to me like the RLU pulls more power (watts) to run the headlight than is needed.
The down side is now the RLU is effectively out of the picture, so if one of my elements where to go out, I would not know it or have a headlight. For me, more light for less is more important than the RLU.
What I also don’t know is if what I have discovered is unique to my XS or typical for all XSs. Anybody else tried this?
FYI: To get the headlight on with the engine off, I start the bike to get the headlight to come on and then use the kill switch to turn off the motor.