George,

Re: 1993 300SD Turbocharger Wastegate?

The 'power converter' sometimes called a vacuum transducer on aforesaid vehicle is located slightly below the passenger-side headlight.
Yes, this part appears to be a modulating electro-vacuum solenoid controlled by the ECU.
Dealer cost ranges between $125 wholesale, $138 retail.
Simple to install--requires less than 1 hour with metric socket set.

Kudos and good luck,

Haltron