Mine work well but I would prefer a switch with a two-level setting. I need one setting when I am wearing a jacket and want to avoid burning my buns off. I need a second, higher setting when I am wearing a long coat.

Some people might argue a "shorts" or "no pants" setting is also needed but I'm not sure that is a really big problem for US spec cars :).

Mine are nice and toasty -- seat and seatback right up to the shoulder blades. Had heaters also in the Recaros I installed in my 2gen, and like the cycle-on/ cycle-off feature on these seats. It's also nice to be able to keep the cabin temp cooler to avoid drowsiness while the seat heaters take care of keeping me comfy.

I'm jealous. :(

They are just O.K.. Warm is about all you get. I don't like the single setting. I think they should have high and low. Your ass burns in the brides Impala. Needless to say, she thinks they stink in the 8.

OK, so I checked the workshop manual. There's a thermostat in the seat cushion near the rear part of the squab (the thing you sit on). A connection is made when the seat temperature is less the 82F (28C). So, if your seat is cold to the touch, the "seat cushion warmers" as they're quaintly called should work. Of course if you've got toasty buns, then Mazda's logic is that you don't need any more heat down there. Next time the car is cold, go for a drive (interior heat off) without a passenger and turn both heated seats on. See how warm the passenger seat gets compared to the driver's seat. If the passenger seat stays cold then you might want to check the heated seat fuse and relay (check your manual for locations).

Mine hardly get warm. The dealer has a test, detailed in the workshop manual to check the thermostats. I think an ambient outside temperature of 28F is enough to warrant warp 10 seat heat. I didn't get that at all but was stuck in a Zen meditation of "did I warm the seat or did the seat warm me?" ;)

Good luck RX-GR8!

Seat heaters
 

I have seat heaters in our 4 different cars incl my new RX8. A VW Beetle will cook you. Our RX8 seat heaters are similar to 2003 Ford Explorer and Jeep Liberty.

thanks for the info. i tried your idea of turning both heaters on and the passenger seat was barely warm. Could hardly tell and ambient temp was around 28. the drivers seat was warm but not that arm. it was hard to tell because i had a heavy winter coat on but touching by hand felt just warm. did you take yours in to have the dealer test them yet or are you going to try to fix them yourself? since mine get somewhat wamr its probably not the fuse but could be the relay or thermostat itself. i wouldnt bother but there seems to be a wide range of temps people are reporting.

If I can find the connector that the thermostat is connected to then I might try the test from the workshop manual. The way I see it there are three possible problems:

1. thermostat is stuck open
2. seat warmers are faulty
3. ambient heat in car is causing seat warmer thermostat to stay open

With 3, I wonder if the difference between people with good seat warming performance and not is that they tend to have their car interiors warmer? One theory might be that the rear seat floor heat vent outlets were heating the seats and turning the thermostat off. I guess another test would be to drive without heat for a while with the seat warmers on and see if they work more effectively.

My bet is that it's faulty thermostats. If I can't prove this by testing I'll have my dealer look at it, but you know how that goes - "no fault found". If there were toasty bunned RX-8 owners in the area I'd also try a side by side test with a thermometer (don't sit on it kids!)