One more observation. The '49 manual says:
1. Washes windshield by twist of the windshield wiper control.
2. Control switch operates with windshield wiper control.
Not sure what the "control switch" is but it seems like my earlier comment about squirting fluid automatically while the wipers were turned on seems likely.
Or, maybe the wiper control switch does more than I think. I admit, I haven't actually looked at it. I just assumed it was a simple vacuum control valve to turn the wipers on or off.
