3sp vs Variable wiper switch interchange.

[mbaird]

I have a 65 B-Body Variable Switch that looks identical to a 68ish A-Body switch. Will they interchange ?
I plugged it in but the wipers wont function ... I did a continuity test as per the 69 FSM and found no connection to terminal B. But I dont know if that is due to a difference internally betwwen the part #s

 

[CFD244]

Does the switch body need to be grounded?

 

[mbaird]

Does the switch body need to be grounded?

Yes I believe so but that should not effect the continuity test which shows terminal B to be dead. The older switches may be different inside.