Here is the wiring diagram.
The best bet would be to power them directly from the battery with their own fuse. This new circuit would have a relay that sourced power from the green wire #6 at the ignition switch. This will ensure that they are only on when the ignition is on.
You should also put a toggle switch for when you don't need them. This switch needs to be in the relay line from the ignition switch.
I have seen this toggle switch mounted on the spare hole of the dash surround.
