Ive done this to mine, see this http://www.lexusownersclub.co.uk/forum/index.php?showtopic=27788&st=0&p=750986&hl=+heated%20+seats&fromsearch=1entry750986
and this,
http://www.lexusownersclub.co.uk/forum/index.php?showtopic=57413&st=0&p=745666&hl=heated%20seats&fromsearch=1entry745666
get back to me if you have any problems and ill be happy to help