The best bet is to run a line off a switched terminal in the fusebox. Find a high capacity line (i.e. a fat wire) and crimp your new wire to the supply (prefuse) side of the fuse and attach a new, inline fuse on your line as close as possible. Then run the line down to your lights from there.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold