Phil,
The car I am working on is the one by my name. It is the 84 300SD. Thanks for the link.
No, it didn't feel like anything at all was happening when I pressed the switch.

I guess I will first try the switch in both directions as Brian stated to see if it goes negative in one direction. If this happens then I will take the motor out and clean and lube it to see if I get any improvement.

Thanks for your help.