My wife drives a 92 740 wagon (non-turbo) wagon, 119k miles. Recently, the central locking mechanism stopped working, intermittently, then completely. The drivers power window switch likewise stopped working intermittently, then completely. Bubba (that's me) decides to fix em.

The central locking I figure is probably the relay, so I search the internet and order a new one for around $42. That was more expensive than the fuel pump relay that saved my butt last year, but still a lot cheaper than the dealer. So I take out the ashtray and look up behind the fuses at the relays and I think I can reach and remove the old one without pulling out the entire shelf, and I am wiggling the old relay... and I hear clicking coming from the tailgate. Yep, the central door locks now work. The relay was just a little loose or had lost it's contact and just needed a wiggle to fix it. And I still have the new one if it is actually going bad.

Now, onto the window switch. Not quite as good here. I try to remove the entire assembly, I know I need to remove the whole thing, but I succumb to the temptation of prying out the single window switch on the driver's side. It comes out surprisingly easily, but of course the tabs that hold it down are now broken. I stretch out the springs a little bit that contact the little ball bearings (what a rinky-dink assembly!!) and put the swith back and now it works... more or less. You have to press down on the switch as you operate it, but it does work, and it wasn't working at all yesterday - window was stuck in the upright position. All in all a successful day for Bubba. :)