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  1. Drick36

    Im not the brightest bulb in the string, but im trying to figure out this driving light relay. I have four connectors on it one says 12volt in,one says ground, one says 12 volt out, and one say on/off switch 12 volt,
    how do I connect the wires ?? by the way the guy at radio shack said this would work it is a 30amp 12volt dc relay.

    I hook the light direct to the 12 volt hot and they come on, but not thru the relay.. I can hear and feel it clicking.

  2. bkman

    Sorry i can't help you more right now - I am at work. Basically, your relay will have four or five terminals. I don't remember the terminal numbers off the top of my head, but one terminal of the relay coil goes to your switch. The other coil terminal goes to earth (Ground ). The other two (or three ) relay terminals are your "big switch ". These terminals will switch the main power to the lights. If your relay has four terminals,you just connect one of the remaining terminals to the battery positive (using a fuse ) and the last terminal goes to your lights.

    I am simplify this somewhat, but hopefully it will get you started. The last connection you make is to connect the small switch to a keyed power source - something that turns on and off with your ignition. You should NOT use the headlight wires for this unless you also put a small fuse on this wire also (less than 2A).

    When I get home, I will check in, but someone else is likely to jump in here before long.

  3. bkman

    Okay, here we go.

    On you relay, terminal 86 goes to the small switch (the one you want to use to turn the lights on and off). The other terminal on this switch goes to your keyed power source - preferably through a small fuse (less than 2 Amperes). If you tie into any lighting circuit for this keyed power source, I strongly recommend the small fuse, which will provide the isolation I wrote about in the "PROS" part of my othe post. You can leave the small fuse out, but your risk of lighting loss goes up significantly, should something go wrong with the add-on wiring.

    On your relay, terminal 85 goes to Earth (ground). Tie it directly to the frame of the bike or some other secure, metal surface that is grounded.

    The wire you use to terminals 85 and 86 can be lightweight - 16 gauge is fine.

    If your relay has five terminals, you will connect terminal 87 to the battery positive post - through a larger inline fuse, of course (15 Amp is fine for your lights), and terminal 30 will go to the positive wire on the lights. Terminal 87a (if your relay has this terminal) does not get connected to anything in this application.

    Two more important things to remember:

    The wires connecting to terminals 30 and 87 will carry the power to the lights. The wire you use on terminals 30 and 87 should be 12 or 10 gauge across the entire run - from the battery post all the way to the lights.

    The fuse you use for the heavy wire must not be larger than 20 Amperes, and it should be as close to the battery positive terminal as possible. Finally, any length of wire between the battery positive post and the large fuse holder will be un-protected and vulnerable to burning if it gets shorted. You would be well-advised to protect this length of wire (however short it might be) with some plastic wire loom (available at most auto parts stores) and a good layer or two of electrical tape.

    That should do it. If you have any more questions, just ask.

  4. wildcatf5

    Great write-up, bkman.

    Maybe that should be copied into the 650 Modifications and How-To's stickey. Just a thought for the mods.

  5. shadowmib78

    I posted a link to a thing for someone else all about relays. Let me see if i can find the link again.

    Here it is..



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