Three switches in the VW Eurovan...same part BTW.
push button switch now....works fine.
Simple to wire on a 914.
Look for the YELLOW wire that goes to the starter from the ignition switch.
That would go on one side of the push button switch.
Run a new 14 gauge red power lead from the battery, up to the dash.
( you could hack this with a splice into what is already there...but I would never suggest that
)
Power on one side, yellow wire on the other.
I always use a 30 amp push button switch...cause I have melted smaller ones....on old starters...and old cars...
Turn key to run, press push button to start.
rich