I tossed a spare into the 'parts bench' of my 84  Vanagon w/inline
Jetta/Golf/Rabbit 1.8liter motor after I bought one to 'trouble-shoot' what
turned out to be a faulty idle control valve.  $40 at a junk yard...Wait, I
should say "Auto parts recycling facility" not Junkyard.
The knowledgeable fellow who owns this Portland, Or.  German-car junkyard
has a book that shows many of the VWs use interchangeable 'brains' and he
says they don't often cause problems, from what he has encountered.  But it
can't hurt to have one along should mine ever fail., they are light, and I
doubt I'd find one available in many of the back road areas I frequent

  Just for comparo, the Porsche 928s I used to mess around with go through
brains all the time and they are about $1000 each, used, with a core deposit
of $500.  The 928 factory 'Bentley book' is 14 full volumes and there are
about 60 relays in a 928...Think about 'trouble-shooting- one of those....

  Don Hanson