Lexus SC430 :: 2007 - Headlight And Fog Light Bulbs Burnt Out Very Often

My friend with a 2007 SC430 has been having weird electrical issues for the past few years. He's owned the car about 6 years now, and probably 3 or 4 years ago things seem to have started acting up:

- the car burns out headlight and foglight bulbs very often, usually after less than a year since they are replaced. It hasn't mattered if the replacements he tries are OEM Lexus or aftermarket, they burn out within a year or so - sometimes within only a few months. He previously owned a 2002 SC430 for about 4 years and never had to replace any bulbs. On the 07, it's usually always one of the driver's side bulbs that will go first, and then within a month or two the passenger's side goes. Sometimes a headlight goes, then the foglight on the same or opposite side goes. Other times a fog goes out and a short time later the headlight on that side goes out.

- his driver's seat heated seat stopped working earlier last year. First the "bottom" stopped working, then a few weeks later the "back" section stopped too. Lexus diagnosed blown heating elements, which can't be replaced without replacing the entire section of the seat. So he found a complete seat from a wrecker and swapped it in. Everything worked fine for about 3 months, and now he is back to no heated seat again (this time both the back and bottom sections stopped working at the same time)

A Lexus dealer spent 4 hours "diagnosing" the car and came back saying all electrical systems are normal, so they can't say why the bulbs are always burning out or why two different seats have stopped working. The car is getting up there in mileage (closing in on 200K miles) but has always been properly maintained.