Inventoring parts is expensive so the trend is to stock larger
assemblies. Fewer stocked parts means lower inventory and tracking
costs, smaller document sets, trouble-shooting procedures that may
be resolved faster and often less technician time to replace parts.
So, it can be hard for us do-it-your self types to just get a bulb
for anything.

This applies to computer industry, autos, appliances, etc.

I have been amazed at the small parts I can get for GM vehicles.
They seem to stock evrything from a panel clip, on up.

The switch lighting on earlier 850's is not serviced. On later 850 and all 70 series, there is a bulb available. Takes 1 minute. Pop the switch out of the dash, turn the bulb holder slightly with a small screwdriver and it pops out. The dome lights are controlled by a switch within the door latches. If the other lights come on, it's not the switch in the door. The problem is within the switch in the light itself. Bad contact on the "door open" side of the switch. The dome/map light switches are not sold seperately. Only available as assembly. The switch can probably be snapped apart and cleaned. If not, you must replace the lamp. The vanity light in the visor has been a problem for many years. Under the lens for the light you will see metal contacts on each side. These contacts provide power and ground when the mirror cover is opened. Often you can "adjust these contacts by bending slightly with a dental pick or small screwdriver and get them working again. Other problems are broken wires at the visor pivot. If adjustment and fiddling don't work, visor must be replaced. Note, most parts guys are commision, so they don't like to waste time on the small stuff. They like to sell "assemblies".

Try the archives. I think the dealer is technicaly correct, the switch is supposed to be replaced as a unit. However, if you are handy with a soldering iron and familiar with Radio Shack's inventory it may be possible to replace the bulb. Check the brickboard archives. The door light switch is integral with the latch mechanism (Volvo's engineers musta been on crack when they had that idea), and I recall it's kind of a bear to fix the thing. Check the archives, too. It may also be in the Haynes 850 manual, itself an essential component of "Zen and the Art of Volvo Maintainance". Spend the $13.27 (Amazon). Don't know about the passenger's makeup light. For most owners by the time they get rid of the car at 150,000 miles half these light bulbs won't work. When you sell it, sell it in the daylight.

-Punxsutawney Phil