Sam, There are two alright.. one big, with the double plug on it.  The other
is a small thing.. with a little nub on it... I took the one out of my old
engine.  So that must be the trouble...?  Yes mine does have a Tach, and the
shaded area is at the bottom of the cluster, and when turned on the hand (
right now ) goes all way to the top of the gauge..?   So that loose brown
wire is for that single wire temp sender...?

Ok, now where does that red wire that comes from the front come from and
go.. there are two female connectors on it..?  ( left side of engine )  It
comes past the firewall, past the black junction box...  a red wire with two
female  connections..?

What kind of a sender do I need to get for mine that part of is evidently
missing??
Lyle Lathem
1985 Vanagon GL