Wire up in general terms
I don't presently have Hella 500s but am likely to get a set here real soon. I have had Hellas before, and the first decision is whether or not to wire using their relay and instructions.
Advantage of their set up/wiring diagrams-when you use your high beams the Hellas (if wired up correctly) will come on as well.
Personally I find that using the supplied instructions and wiring it their way is a pain in the butt. I like to use my driving/fog lights on low beams at times or separate with no headlights at all. So I have always wired my auxilliary lights to my own switch-typically substituting their supplied wires with smaller numbered wiring (thicker wire). I frequently use 'safety switches' which are only accessible after first flipping up the toggle switch cover protecting them, so they can not accidently be flipped on by my dog for example.
The switch and both of the lights must all 3 be grounded-typically you can find an inside grounding location near or on the firewall for the switch itself. The lights will either ground directly to your bumper/brush guard or run a separate ground wire to a location under the hood.
For power- always use an inline fuse holder of the same size rated for the lights, some folks recommend a relay as well-personally I avoid them. I typically run a power lead direct from the battery with a fuse under the hood and protected from the elements. This allows the lights to work anytime-and are not dependent on the headlight wiring in any way.
So a switch will have 3 wires-
1)a power supply from the battery to the switch. (long wire-typically red to indicate power)
2) A ground wire for the switch to the firewall.(short wire)
3) Power to the device-the lights (long wire-frequently but not always white) This wire will be "split" to feed both lights.
If you have more than one wire leading out of your light be sure to verify which is the ground and which is the power (input) so as not to short them out. If their is only one wire, then it is for the power and the lights ground themselves at the point of mounting to the bumper/bull bar.
I hope this helps and did not confuse....
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