Friday, July 4, 2014

Dual Headlamp Wiring

Ok so it’s been awhile (AGAIN….) and im not gonna bother starting by saying sorry coz I’m working… it’s not like I have a choice or anything, if I don’t work, I cant ride… anyway, so last year I had installed my dual projector headlamps. Earlier when I set them up, I had assumed that the HID high beam would be able to replace what the halogen low beam was covering, unfortunately, after a while, I found that the HIDs reach started where the halogen stopped, thus leaving a large black hole in front of my bike in the dark. A year plus later I finally found the time to do some work on it to fix it.. and it wasn’t easy trying to figure out relays… this was because of my limited knowledge or relays and the lack of stepping out of the box to see the picture. Now that I know how it works, I wish to share this to you who want to know. This may look easy, but it wasn’t when I was figuring it out. I finally buttoned it up at 1am starting the project at 5pm.

So what you will need is the basics of a relay, there is a picture of one and its rough descriptions as stolen from

Now, the fact is that this is the general idea of how a relay works, but what you must understand is that electricity flows both ways, thus a relay can function backwards as well.

So what do we want to do? We want a single headlamp to turn on during low beam but both headlamps on during high beam.

Question: simple, why don’t we just jimmy the high beam wire to the low beam signal so it will turn on when u flick the high beam?
Answer: electricity flows both ways. With the signal to the low beam on, the electricity will flow back to the high beam signal triggering it. Both lights will be on all the time.

Question: Why not put a flow diode on it?
Answer: A light drains a lot of power. More than a diode can handle, it will blow quick

In my case, I had HID on one and a normal halogen on the other thus the HID needed a relay of its own to juice up the ballast.

Please refer to the pictures:

Step 1:
Join 1 and 2 to the low beam signal.

Step 2:
Join the high beam signal to 3 and the high beam bulb/6

Step 3:
Join the low beam bulb positive to 5

Step 4:
Join 4 and 8 to negative (ignore 8 if you are not using a second relay)
*if you are not using any extra relays (normal bulbs), then you are done here)

Step 5:
Connect 10 to your battery (preferably with a fuse)

Step 6:
Connect 7 to your HID positive

If you still don’t understand, please refer to this more crude drawing:

** if you wish to have a relay to power a higher capacity bulb or HID, then in Step 3, connect 5 to another relay at 85 or 86.

By Vy

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