I didn't. I spliced in to another 12v constant source from under the dash. The kit I got supplied an in-line fuse for this and yours should too. To be honest, I don't remember what I spliced in to, but just poke around with a multimeter and find something that has 12 volts when the ignition is off.Thanks, this really helps.
So you just spliced into the wire supplying power to the dome light?
Sorry but I just wanted to be sure. I want to do this job right. I'm not too familiar with electrical work. Everything else seems pretty straight forward.