How do I tie accessory wire into fuse box?

[davepl]

I like to ground mine through a relay triggered by the oil pressure sender. That way it won't heat & open the choke just because the key is on, but rather, needs to be actually running for the choke to heat.

I probably wouldn't go to that length JUST for the choke, but if you've already got an idiot light sensor (doesn't work with a gauge sender), it's a simple mod.