As colder days are coming along here in Vancouver, BC, I started using my heater in the steering wheel. Well some mornings it does not want to turn on. I push the button, and the green light comes on and after about 10 second it goes of. Next time I start my car it works fine. I've been talking to the service guys, but they can not find the problem, as it's intermittent. Any thoughts?

It is a 2009 X5 35d.

Thanks guys!