New-to-me 914 gets warm air on the RIGHT side windsheild defroster when I pull the red lever below the shifter.....

but the lefft does not seem to get warm at all.

Where should I start looking for a fix, typically?

Cheers.

Check the hoses. The factory ones are notoriously flimsy. Possibly just detached. If not check the wires to the diverters. These control where the air goes. From your description I would suspect the hose.

Also if you need them I have more robust ones here -

http://shop.914rubber.com/Hoses-from-blowe...f-2-914HHLD.htm