'86 Coupe GT questions

[auditude at get.net]

Hello all,

The patient is my '86 Coupe GT.

My oil light is now permanently on.  There is no buzzer sound, but I believe the relay for that feature is
missing.  Oil pressure and level looks normal.

I swapped the two sensors on the side of the block out with the ones from my old Coupe GT motor, and
no change.  I'm not sure which sensor measures which thing.  The one is a smallish sensor with a single
male blade connector, while the other one is a somewhat "can-shaped" sensor with two such male blade
connectors on it.

Since these sensors seem to always go bad, the ones on my spare motor are probably bad as well.  But
I'd like to know what sensor does what.  The Bentley only seems to show the smaller of the two, and the
location for it in the picture doesn't match where I found it on my car.

I'm also curious as to what the sensor does at the rear of the head.  It is a brass nut-shaped sensor, with
the standard Audi connector that locks in place with a wire device.  The same type of connector that is on
the ISV.  What does this sensor do?  It was disconnected when I got the car, so I plugged it back in.  I
can tell no difference either way.

I think the other dash cluster that was in the car probably had the oil light missing from it, unless this
problem just cropped up.

Any info would be appreciated.

Later,

Ken