Power to Motolights

[harpo]

I am about to put my Motolights on my 03. I was wondering where is the best place to tie in power to the lights? Is there a accessorie wire on the 03 that can be used? or is splicing into the head light wire the easyist.

 

[dcarver]

Not that familiar with Gen 1 bikes but..

You might want to consider tapping into a running/tail light wire and not the headlight wire. Of course, use a relay for the big lights. Should your headlight circuit fail (not all that uncommon), you can get home on the aux lights.

yeah, I got stranded once, O'DarkThirty, the headlight circuit fried, could not get the Aux lights lit.....

 

[Bounce]

Do you mean main power to drive the lights or an "activation" source to turn them on/off via a relay.

NEVER tap into the bike's harness for main power. OEM wiring tends to be rated to barely cover the load they carry from the factory. Lights (good bright ones) tend to carry a decent load of their own. Run a 12 ga wire from the battery, to a 30a relay (overkill I know), then from the relay to the lights. Run the "energizing" control wire (which is lower load) from the "arming" side of the relay to high or low beam circuit or to a switch mounted somewhere appropriate. Don't splice into the harness since that can lead to corrosion. Lots of folks like the Posi-Taps for a less obtrusive way to grab that low voltage line.

I'd tend to the stand-alone circuit with a switch that controls the lights and breaks the switch circuit with switched power (from the windshield auto-retract jumper) to keep it from being left on when the ignition is off.

 

[Fred W]

+1 on what Bounce says about using a 12V relay to control the power to the lights.

For the (low power) signal wire controlling the relay, I used a SPDT On-Off-On type switch in the dash panel. The switch was originally installed in the dash to control some heated grips, which I later rewired to use a heattroller for more variation of the heat. But I digress...

The switch was wired with the common going to the relay trigger and one side coming from the high beam headlight power signal, the other side coming from an ignition switched 12V. The switch was also labelled High and Low with the center being off. In the High Position the lights would come on and off with the High beams. In the Low position they would come on and off with the ignition (so always on), and in the center they would remain off.

If you have your aux lights aimed high, as driving lights, you may want to have them come on and off with the high beams to prevent blinding oncoming traffic.

Here's a schematic of the wiring:

 

[harpo]

Thanks for the good advice,glad I asked before just diving in.

 

[Brodie]

One thing I may add to this discussion...

Be sure to run the ground wire back to the battery negative terminal. Do not tie into any of the existing ground wires on the bike, the same argument holds true with these marginally sized wires as with the "hot" side of the circuit.

Brodie

 

[Fred W]

Good point about the ground wires. They have to carry the same current that the power wires do.

For lights and heated gear, I am not opposed to using the frame as ground.

For any sort of sensitive electronic gear I want to use wires all the way back to the battery, or a buss bar that goes to the battery.