I have replaced all my switches on my '99. It was driving me nuts - one window switch sizzled and smoked, another stopped working. I reversed wires in the door cluster for the rear side because the master IS dependent on either British or American, and being such as the British I had bought the wrong master. That still didn't work - you must get RH (Brit.) or LH (U.S) master. I have cleaned contacts. I replaced the conductive contact pin under a lever with a nail. Watch out for the tiny spring inside the pin casing! Then, soon after installing a brand new passenger switch, it failed, by going up but not down. I pried it with an awl, blew into it, tapped it, and it got working again. But that was the new one; sad to say it, no matter what I did with the old switches I could find no satisfactory cure. I have had to buy all new.