i've noticed this for quite a while now, but whenever i wash my car (or am just around my car at any time for that matter) my car occasionally just starts making this weird ass humming noise. i can't really describe it, but it sounds as if something metal is humming. there's no pattern, it just does it randomly, like every other 10-20 minutes. has anybody else noticed this or knows what's causing it? sounds kinda like as if the seat is moving forward on its own

 

might be a selinoid(sp?)/motor, could have to do with the evap system or the hvac system.