[johnnyAtStreamfield]

Hi, looking for some advice if possible.

I bought some F21 power seats from EBAY and thought I'd test them before coding into the car (current seats are only heated - different power pins and single LIN BUS pin rather than the 2 CAN BUS pins on the new seats).

My understanding was that pin1 (bottom left in the pic) was 12v 10a for seat width power, with the spade pins 15 being 12v 30a and pin 16 for ground. I wired these up using fuse taps to the car battery, and also wired pins 5 & 6 to CAN Low & High. Checked voltage using multimeter and all is good, however on testing absolutely nothing happened.

Judging by other posts, I'd have expected the electric adjustment to work just by supplying power, before doing VO and ECU coding.

Is that correct? I don't want to start coding if the seats are duds.

[johnnyAtStreamfield]

So I finally "bit the bullet" and completed rewiring and put the F21 electric seats into my F23 car:
Pin 1 12v 20amp for seat-width power.
Pin 5 & 6 for CAN Low and High (I tapped into the CAN in my iDrive controller - little bit fiddly bit worked fine and easy to test by putting a multimeter across the new CAN Low & High cables with the car battery disconnected, and should get around 60 ohms resistance.
Pin 15 Spade 12v 30amp positive
Pin 16 Spade Earth.

I had to ensure the actual seat plugs were also installed into the car seat harness (i.e. the seatbelt and occupancy sensor etc were attached).

I then used ESYS to code 459 and 481 into VO, then coded ECUs for FEM BODY and HU. ESYS also found two SM2 ECU modules (I assume both driver and passenger seat modules) and I coded those.

The electrics sprung into life. I found that they would go backwards fine but only forwards in tiny notches - I had to calibrate the electric seats (you basically have to keep pressing the seat control forward until it's fully forward, hold for 15 seconds, then press the seat control backward until it's fully back, then hold for 15 seconds. After that the seats worked fully.

It's at this point that I found out the seats weren't heated (as advertised by the breaker). The lights on the buttons came on for about 2 seconds (and I heard the car relay activate), then went off.

A real shame since heat matters more to me that electric control. So I've stripped the lot out again, reinstalled my old seats and recoded.

Looking on this as a learning experience rather than a waste of 4 hours of my life!