I had some years ago mounted a simple electric washer pump up under my driver's side fender by removing the panel in the wheel well so the pump was hidden from view. I then just fed a hose up to the washer bag mounted on the same fender well in the engine compartment. I removed the old vacuum switch from the dash trim cowling and installed a momentary on/off/momentary on toggle switch in same cowling location. I was able to remove the toggle from the elec switch and fabricate the original vacuum toggle and trim plate to activate the elec toggle switch. My wipers are still yet vacuum wipers and are activated by the original control knob on the dash.
'58HT and '48 Dodge Panel in MN
Thunderbird Registry #3810 VTCI#7652