You should have only  the 0.3 bar switch down on the case--only the 86+ had
the second switch back by the oil pump.  Check to make sure the switch is
normally closed (continutity through switch with no pressure) and opens up
with pressure.  Does it light up on the dash with the key turned on?  It
should be on and then go right out when the engine catches.  It is not
unusual for this light to flicker or even stay on when the engine is hot at
idle, but it should go right out above idle.  It should never come on when
driving (0.3 bar is only about 5 psi).
                                                   Jay