So, from the parts list you posted, it sounds like you don't need a high current switched source? The switched source just closes the relay?
Correct! :clap:
Any suggestion on which switched source to use?
very much a preference thing... whatever you are comfortable tapping in to. Since you got the relay idea, I'm guessing you probably have at least as much electrical understanding as I do (not saying much there, but it doesn't take much). A number of possibilities... On the front side, you have the brake light actuator on the throttle handlebar, Running light harness on the inside of the fairing, horn circuit, dash power, hazard switch and probably about 20 others. On the rear end, I'd go hunting for the running lights - Real easy to find and the wire goes just about everywhere you could want for tapping into it.
Since I don't have a spare fuse socket (switched or otherwise), I can't just grab a signal there. It seems like I'd need wire the relay in series with one of the in-use sockets (moving the fuse to the new block)? Or maybe I need to splice into a switched source and wire in parallel with the fuse?
Not sure I understand you here, but it doesn't really matter. Just slap a fuse inline from the battery to the main power on the relay. RatShack sells the inline mini fuse sockets for $5 I think. Nothing to it. Fuse as close to the battery as possible (making sure you can get to it quickly if you need to of course), then run the relay off that.
Are there any complete kits do do this or do I have to go buy parts?
None that I know of, but the entire batch of crap can easily be found at RatShack, although you might want to hit an auto part store for a better relay.
I'd still be interested in hearing ideas that don't involve installing a switched distribution block, at least for temporary use. I need decide soon if I have to return the seat (14 days minus days elapsed from last Saturday) and I'd like to be able to use it for a few days before that deadline. Like, is there some type of Y-connector that would allow me to connect a fuse plus a pigtail into an existing fuse socket?
Okay, here's an option, but it's at your own risk... *I* wouldn't do it, but I'm a bit of a paranoid freak.
The Yamaha heated grips operate off the brake light power circuit. They'll burn the halibut out of you on high, but I don't know what kind of draw they have. Suffice to say, the brake light circuit can handle that. It
might be able to handle the seat heat. Not real sure, but if you're desperate and don't want to wire up a relay, it's an option. Of course, if someone were just trying it out to see if they liked it, they could just bypass the bike circuitry all together and wire it straight to the battery with an inline 30 amp fuse and a manual switch. As long as they remember to always turn it off until they've decided to keep it and wire it correctly. But you didn't hear that from me.