Question regarding switches under the dash pad on a 65 Riviera

[Seafoam65]

My 65 has the courtesy light switch on the left side under the middle of the dash pad and the power antenna switch on the right side under the dash pad, with a place for a third switch between those two

that is empty with the mounting holes showing. What option or options could have been in this slot, and how was it labeled?

[telriv]

IF I remember correctly that was for the rear defogger. 1st. postion was low 2nd. position was high lower. I believe it said rear defog.

[jframe]

Yep rear defogger switch went there, marked "accessory". What puzzles me is I have seen so many of these cars with those switches in any of the three positions available. It's like the factory just threw them it whatever slot they picked first.

[telriv]

Your Right Mark. I forgot it said accessory.

[Paul K.]

Its been 30 years since I sold this car but pretty sure our 65 GS with AM/FM had the radio reverberator switch or maybe it was a knob mounted there. The marking said "Reverb".

   

[RivNut]

Here's a picture of a '65 Riviera dash that shows the reverb switch just to the left of the ignition switch. Same place as on my '64.

[Paul K.]

Interesting Ed. I would remember one like that which is nothing like the one I had. I'll look for some photos. 

[RivNut]

I have the reverberator, all the wiring, and installation instructions in a box on the shelf. That's the switch that came with it.  The first time I saw it I thought it was too cheap looking to put in a Riviera.  Perhaps someone came up with something a little more classy.  It is basically on and off so a courtesy light switch could be made to work.  Did the bezel have "reverb" or something similar, or 3as there even a bezel with it?  

[71GS]

Ed, I had a 64 with reverb ad it was exactly as the picture you posted also. 

From everything I’ve found, the center switch/ space under the dash was for the rear defroster and read accessory