I just happen to have a set of heated seats from my SE Exec next to me, so allow me to chuck my 2p in :lol:
Under the seat you should have 2 connectors as below.
Yellow is the side airbag, I don't know if the S trim level has these but if it does you should have a connector for this, and if it doesn't you can just leave it unplugged. The grey connector is for the heater elements - there's only 2 wires so I'd ***ume it's a 12v feed and an earth required. For each seat, I'd run a fresh fused 12v feed from the fuse box into a relay and then on to the grey connector (attached using a small female spade connector to the pin in the connector)
Then just run a wire back from that connector to the closest possible earthing point.
You'll then need to sort out switches, I don't have a pin-out for these handy (and I'm not walking out to my Prelude :lol: ) but you'd run another independant 12v feed into the switch, then wire the switch to the relay (that you previously wired to the +ive feed for the heater element) and then earth it. There will probably be a pair of pins for back lighting on the switch too, I'd wire these from something such as the ciggy lighter light as that's turned on and off with the side lights.
Sorry that this is a bit vague, I'm shattered and find it a lot easier to explain these things verbally! And also please don't hold me liable if everything catches on fire :lol: My auto electric skills are self taught, but I've retrofitted power windows to my golf along with some other little projects, and I'm currently fitting heated seats to my Prelude
