Ever since I bought my 93 CBR couple months ago, I've had problems with the headlight not coming on. I know they work, because I changed the bulb's and they have came on one-time while riding. So for the past couple week's I have been researching and buying part's to rewire my headlight. I could have simply traced the wire that was loose, but I opt to rewire-just for the sake of research and curiosity of how a relay works.
I understand that there are diffrent ways to wire up a relay, but this is the way it work for me.
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Above: This is the commonly used bosch relay- I got the one is rated at 30 amp-these can be found at your local automotive parts store for ~ $6.00. The switch is an on-off-on switch, used for my Low beam, off, and High beam- The yellow wire in the middle is my power wire from the relay # 87 (accessory) dont know if its necessary to add a fuse, but I did-just in case. The switch I got for ~$3.00 and the fuse ~ $5.00.
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Above: Here is the switch and three prong universal headlight plug. The yellow wire powers the switch and gives charge to nothing if on the off position (middle) and power to Hi (in my case up) or Lo (in my case down). The wires for Hi and Lo, goes to my three prong plug.
If you were to look at the prong from the back, in a pyramid shape (single wire at top), the single wire at the top is my low beam, the one on the bottom left is my ground wire coming from the relay #86 (I also spliced another wire to this ground, which I grounded to my bike chassis) the wire on the bottom right is my high beam.
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Above: This is the Bosch relay- I bought the one with five posts, a relay with four posts would work, because I didn't use the one in the middle (87a). As you can see in the picture- the wire I labeled as my main power goes to the positive terminal of my battery- its #30 on the relay. You can see it better on last picture below.
I spliced another wire to my ground- one wire goes to the three prong headlight plug and other wire to the chassis- it is # 86 on my relay.
#87 is my accessory post- the yellow wire is fused and goes to my On-Off-On switch.
The picture does not show a good description of my #85 switch. This is what turns on my relay (actually #30 powers the relay, but #85 is the one that completes the charge- a relay is essentially a switch.) It is wired to my ignition, so when I turn on the bike, the relay turns on my headlight. I thought about wiring it to a switch and having the independance of turning on/off my headlights at will- but not right now. If you would like to do that, instead of wiring it to your ignition, make a jumper from the #30 to your #85 with a switch in the middle.
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As you can see this is the bottom of the relay.
#30- I have my main power from the battery- with an inline fuse.
#85- This I connected a wire from my ignition.
#86- This is my ground. (Also, I have found out that you are limited to using 85 for power and 86 for ground- it could be the other way around-this is just how I chose to connect it.)
#87- This is the accessory or for what ever you chose to power up- in my case- rewiring my whole headlight system.
#87a- This is for constant power? from what I understand, there will always be power coming out of this terminal...thats why I chose not to use it. Please correct me if I'm wrong. I had no use for this terminal, so I skipped over this part.
More when I get back from a meeting.
