Supershuttle I had the same problem with mine, does the cooled setting stay on indefinitely and then the hot turns off about 30 after starting? If so it's a faulty thermistor on the seat back fan assembly!
New unit I'm afraid,!  2006 RR sport HSE
Swapped for 2012 4.4td v8 Westminster Santori black with Ivory leather
BEEN SMILING EVER SINCE

Thanks Steveball - Although my issue is a bit different, for the most part it works fine and when the seat goes off, so does the dash light.

I'm wondering if it's got something to do with the "Prog" or "Auto" setting in the middle of the fan control. After 10 years of L322 ownership, I still don't know what that does, maybe I need to look at the manual.....

I'll get the seat out over Christmas and see if its broken as described by others first, if so I'll try the "fix" as this costs nothing but time then if it doesn't I'll be back on here asking for part numbers for a new unit. I feel that its a bit more sensible approach rather than pressing the panic button and sourcing a new unit now. Geoff

The good news is I got the seat out and the back off and located the busted pipe. The bad news is it's just started down so I have had to cover everything with a tarp and get back to it. Its worth noting that getting the seat out is not quite as simple as it seems, I had to drill a hole to release the seatbelt and disconnecting multi plugs is always a pain. Geoff

So I fixed the busted pipe as others have done - BUT no joy as the fault remains. So I'll try swapping the ECUs but I'm not optimistic so I'm bracing myself for another big bill  Geoff