Heated leather sports seats

[trapdoor]

I have tried to find a definitive answer to this, but just can't get my head around what parts I need to retrofit the heated sports seats.

The retrofitting kit on the ETK states that you need additionally, the switching centre (I have) and new seat covers. However, no amount of searching in the ETK on all dates/markets of E83 show any part specific for heated seat covers under the Seat Upholstery section.

It was rumoured several years ago (for the E46) that there was no difference, and that all covers installed by BMW after 2002 had the heating elements built in, but I have never found out whether this was true, or whether it is true for the E83. Surely if the ETK doesn't show parts for the heated seat covers, but only shows 'seat covers', then by deduction these must have the heating elements built in?

Be interested to hear from anyone who has pulled out their seats who don't have seat heating, whether the wiring is there under the seat but just not connected.

TIA.