I just finished putting an engine in a 2002 subaru outback wagon.  I have a extra pair of heated seats and the switches the same color and wonder if anyone knows if there is wiring for the heated seats already under the seat.

I can't see any wires under the seat other than electric seat power.  Does anyone know if the factory ships them with the wiring?

maybe under the console? that's where the switches are on my H6 03

good call.  That will be easy to look for as well.

I added a heated element to my 95' Legacy out of I think a 98' Outback. In that case, there were only 2 wires FEEDING the switch (ground and 12v+). Wires after the switch went directly to the seat. I only did passenger seat though. Hi/Low heat function works (it's controlled in the switch), and I just wired it to the cig lighter's 12v+as I never use that, and it's rating was sufficient for the one seat. Temp control on/off (if like the 98') should be controlled via the actual seat's heater element. It needs to be AT a certain temp BEFORE it'll kick on, meaning the heat generated while sitting on it IIRC. Mine won't kick on w/o me on it. They have an auto-off to prevent overheating. A way around the auto-off is leave windows cracked so fresh air enters (leave dash heater on or low) and the seat should remain on indefinitely as it won't hit the high-side temp off.

 

Need to verify BOTH seats actually heat up. A common failure spot is on the lower seat area, DIRECTLY between the thighs/knees (closer to knees). As the seats pull apart over the years, the wire in the heating element can pull apart, creating a break. This will prevent the seat from heating. I had this issue on mine. In my case, I carefully exposed the wire break (it'll stain the white mesh brown if it arced a few times and is visible), and soldered in a new section, making it longer than the original break. The factory wire is like 24 gauge (reason why it gets warm when intentionally shorted to create heat) and I soldered in something like 18 or 20 gauge, then sandwiched that on both sides with black Gorrila tape which is a heavier duty and thicker tape than standard duct tape, to prevent the splice from ever pulling apart.

 

Anyhow, 3+ years later and it's yet to fail. It's also NOT detectable from the outside.

Also, if my post wasn't clear, I had to harvest the wire harness from donor vehicle. I took everything feeding the seat(s), took the seat heat switch assembly, and think I cut or disconnected as far ahead the switch as possible. My 95' did not have any of the needed wiring.