You have two oil pressure sensing switches.
The low pressure switch (4.4) must open between 2.2 and 6.5 psi.
It is located between cylinder 3 and 4
The other switch (13.1) must close between 10.9 and 14.8 psi.
It is in the vicinity of the oil pump.
The flashing LED is associated with the 4.4 sensor.
The flashing LED and the buzzer occur with RPM>2000 and no switch closure
from the 13.1 sensor.
A loose connector in the engine compartment gave me the LED/Buzzer
symptom .

On Thu, 2 Jan 1997 14:17:50 -0600 cbennett@kpmg.com writes:
>Hi there,
>
>I have experience problems with my oil light and buzzer coming on 
>while driving
>my 86 Vanagon Syncro, and I've concluded that it was because I was 
>using too
>thin oil for the temperature outside.  When I use 20-40 it rarely 
>happens.
>
>But I am still wondering why are there two oil sensors, which I am 
>told measure
>too high as well as too low oil pressure on the engine. I can 
>understand too low
>pressure, but why would they want to warn the driver if the oil 
>pressure is too
>high?  I never understood that.  Can anyone explain it to me?
>
>Thanks,
>
>Charles
>
>