That one in the photo doesn't look like anything German I've seen, and if you opt for a VW German one you'll still have the issue behind the dash as those all expect to go into a 19 gauge piece of metal.
You have what appears to be the equivalent of a Standard Auto Parts DS-121 (which is made for 6 volts). That might 'splain the pitted/corroded contacts inside.
Standard also makes a 12 volt version DS-135.
Either is a "universal" switch, not specific to any make/model. Both have that fuse on the back, although the 6V version should have a slightly larger fuse (like a 20 amp).
For sure, NAPA can look those up and see if they either have one or can get one. They may have dimensional specs on-line, too.