there is no such thing as a two wire screw-in temp sensor for a vanagon.

take your yellow/red temp sender wire and connect it to the single
contact on your screw-in temp sensor.
I think it will work just fine if you don't even connect the brown
ground wire..
I think that  goes to ground anyway ..
but you can ground that brown wire .

can sell you a plastic 2WD t-stat housing if you wish, new.
the metal one is better. Obviously.
the plastic ones shrink, dissolve, and generally fail in silly ways,
eventually.

Don't overthink it.

cat converter cable ???  No wires go to the cat.
perhaps you mean oxygen sensor .
that connector is easy to identify ..
the green coax........that's 02 sensor signal  feed to the ecu.
the double plug is 02 heat.
anytime the engine is running you should see 12 volts there.

On 5/2/2013 8:12 PM, Steve Cotsford wrote:
> OK  I think I have solved my mystery connector issue.   Dennis put me on the right track.
>
> I have discovered that my engine is from an '86 syncro.     As such, it has a METAL thermostat housing and a temp gauge sender that just has one wire (fits like a nail head on the sender instead of a plug.     This sender screws into the housing.
>
> The van is an '89 2wd and presumably it had a PLASTIC thermostat housing on the original engine.   It seems it had a 2 wire temp gauge sender as the wires in Bentley jive with this (two pin, red/yellow and brown wires).    The sender would have been held in place with an o-ring and clip.
>
> What I need to find now is a two wire temp gauge sender that threads into the metal thermostat housing.   Alternatively, I need a plastic thermostat housing to take the place of the metal one, so I can install the sender that gets held in place with an o-ring and clip.
>
> Does anyone know if in fact there is screw in two temp gauge sender ?       If there is, I believe it would be for a 1987-1991 syncro with metal thermostat housing.
>
> Its confusing that both the temp gauge sender cable and the catalytic converter cable have plugs with same color wires (red/yellow and brown) as well as the same kind of connector.    Only the length of the pigtail differentiates them.
>
>