I should of said under the passenger seat it's a bit tight for the drivers seat all the heated cables and movement stuff I used the front part of the seat drew to front it put a seal on to stop vibration my wife said it is quite pleasant i don'n know why ??
Can't say for sure as never changed the same, but I'd say just change it. The system should re-test/reset itself after replacement. That said, I'd remove battery connection whilst changing to avoid any spurious signals/jolts over the CANBUS to be safe.