Lighting Switch in '51

['51 Special]

My 51 Special is getting more and more fun to drive (particularly with a front-end kit installed by someone who understands kingpins). That gets me into details that I have previously ignored. Here is the latest: the lighting switch.
Mine currently works just fine for the headlights/parking lights/tail lights. But, the map lights come on when they shouldn't, the dash lights and clock light now won't come on at all, and the dimmer function seems to have given up when the dash lights and clock light quit working. Note, please, that two of the dash lights, the clock light, and the dimmer function worked just a few days ago, while the map lights wouldn't work at all. Note, also, that all of the lights have good (tested) bulbs.
I have not yet taken the switch out, though it is clear that the functions that work by rotating the know are not operating smoothly, because the book says: "If a switch is faulty it must be replaced since internal repairs cannot be made."
Checking for replacements, I find none that accommodate the map light function. All new switches I have found (including the ones that promise to be exact replacements) have only four output terminals. Thus, there are sources for powering parking lights, headlights, tail lights, and dash lights (which have a dimmer function) but none have the fifth source for the map lights. I know I could just put a separate switch somewhere to operate the map lights, but would prefer not to. So, two questions: (1) Does anyone actually rebuild these things; and (2) If not, is there any known source for fully functioning replacements (other than NOS and used take-offs)?
Thanks for any ideas.
'51 Special

[suntreemcanic]

I have a 52 Super, I would bet the headlight switches work the same. It has six positions rotary turning. Turning the switch counter clockwise completely to the left 1st position no dash lights nothing. Second position turning right map lights, third position map lights brighter, forth, fifth and sixth positions are different brightness of dash lights clock included clock. It was necessary to turn on the parking lights or head lights to get the dash or map lights to function. My dome light is controlled by the doors or by a switch on the 'B' pillar behind the driver seat.

Cars that had mechanical head light switches of the 70s and 80s had a switch that when turned it dimmed the dash lights and another position to control the dome light. I think a modern switch would work for you using the dome light terminal to control the map light. You would have to play with the new switch to figure out what each terminal was for to hook up the proper light to it. You would also have to fit your dash knob(that would be the difficult part). But I think it could be done.

['51 Special]

I have a 52 Super, I would bet the headlight switches work the same. It has six positions rotary turning. Turning the switch counter clockwise completely to the left 1st position no dash lights nothing. Second position turning right map lights, third position map lights brighter, forth, fifth and sixth positions are different brightness of dash lights clock included clock. It was necessary to turn on the parking lights or head lights to get the dash or map lights to function. My dome light is controlled by the doors or by a switch on the 'B' pillar behind the driver seat.

Cars that had mechanical head light switches of the 70s and 80s had a switch that when turned it dimmed the dash lights and another position to control the dome light. I think a modern switch would work for you using the dome light terminal to control the map light. You would have to play with the new switch to figure out what each terminal was for to hook up the proper light to it. You would also have to fit your dash knob(that would be the difficult part). But I think it could be done.

Thanks Suntree. I checked several service manuals I have for later GM cars, and found they typically controlled the dome lights at the headlight switch. Great advice.
Update: I removed the switch from the dashboard (but not from the connecting wires). A close examination found significant corrosion on the visible fixed contact for the dash lights, and less on the visible fixed contact for the map lights. The non-visible contact is on the moving part of the switch. I dug out an old emery board and cleaned up the visible contacts. Then, holding the emery board over the fixed contacts, I rotated the movable contact back-and-forth over the emery board. This produced a quantity of corrosion debris on the emery board. I blew everything clean and re-installed the switch. It now works just fine. Took about ten minutes. Lesson learned.