I have to replace the wiper motor in my 1972 Cutlass. The choices at Napa, Auto Value, etc., have listings for one w/o washer pump & w/demand pump & one w/o washer pump & w/o demand pump. What is the demand pump?

 

It was a gadget, but I thought 71 was the last year for it. Also referred to as "shift lever controlled windshield washer".

It had a button in the end of the column shift lever that actuated it. Push in to the first stop and the wipers would make a single pass across the windshield and then park. It would also cycle as long as you held the button.

Push it all the way in and it actuated the washers. The washers and wipers would then go thru a normal wash cycle and shut off.

Think it was 72 for the B-C-E cars and 73 for the A-bodies that the demand wiper became standard. If you see a car that has a "MIST" position on the wiper switch, that is also "demand" wipers. Push the switch down to MIST and wipers will operate as described above.

For light mist or rain conditions it was worlds ahead of constant-speed wipers, but still not as good as the later full delay wiper circuits.

The difference in the motors is the circuit board. If you don't have the shift lever control or later "MIST", you need the one without demand pump.