I know this is not too much help for finding the source in
the engine compartment, but FWIW, under the dash, the wire
bundle behind and just to the right of the steering column
contains the wire that runs the tach.  In my '85, it is the
only solid green wire in the bundle.  I needed a tach signal
to drive my cruise control computer, and after much probing
around I found that wire to contain the tach signal.
--
Bill Knight
Raleigh, NC

84 Westfalia Wolfsburg
85 Vanagon GL

John H. Fleming wrote:
>
> Can anyone tell me what the input signal is for the Tachometer on my 85
> Westy?  When installing the subaru 2.2 in the Vanagon, the "signal from the
> Subaru is too weak to drive the Tachometer."   Kennedy Engineering
> recommends an aftermarket Tach, uck.
>
> I would really like to use the Subaru signal on the existing Tachometer and
> would consider an amplifier or signal conditioner to make it work.   Maybe
> a schematic of the existing VW computer output circuit would help, too.
>
> TIA
>
> John Fleming
> 85 Westy
> 79 camaro
> 54 Ford P/U