Conrad,
You're talking about the temp sensor in the thermostat, yes?  There are two
sensors there (at least on my 2.1): one faces towards the front of the bus
and is for the fuel injection system.  The other faces towards the driver's
side and is for the temperature gauge on the dash.  I might have these two
confused because I'm not leaning over the engine at the moment.
The connectors for both of these are the standard Bosch two-pin spring clip; I
hear tell these are available at your FLAPS, but here in Boston mine are all
crap (aisles and aisles of bling clamp-on tailpipes).
If this isn't the wire you're thinking of, perhaps you're talking about the
temp sensor which lives on the driver's side of the block, under the pushrod
shield?  That's just a single-spade connector with a rubber boot on it.

Best,
d.
1990 GL -- "Mudskipper"