1973 450 SL Washer Switch
 

Help. Just acquired a 1973 450 SL that was in the process of restoration. The guy I got if from did not remember how the foot-activated switch for the windshield washer mounted. The switch works fine, but it is mounted on a long plastic "cover" that looks like it would either mount along the threshhold below the hood lever or perhaps up under the emergency brake brackets. Can anyone help tell me where this mounts?

I'm thinking it ought to mount against the floor/firewall, top left corner - like the old fashioned american high beam foot operated switches.