First, realize that the 2 switches work in opposite ways. The low switch
is the normal kind, grounded when there is no pressure, open when
pressure rises. The high switch is open when there is no or low pressure
and grounded when the pressure is high enough. This is sort of a
failsafe type design since the old method gave no warning if the wire
was unplugged from the switch but the newer type triggers the alarm at ~
2000 rpm if the high switch is unplugged. Since both switches are wired
to the same 2 pin connector, leaving that connector unplugged is
detected by the new system. The low switch is always monitored but the
high switch is only checked when the rpm is above ~rpm. If you check the
2 switch signals at the 14 pin connector you can check at the dash and
make sure the signals are reaching it. u With the lower cover off the
steering column you can unplug the 14 pin connector and hang it down
under the dash where you can probe it with the cluster still in place.

Mark

Al and Sue Brase wrote:

> I've now got a related problem:
> I just changed the engine in my brown 87, putting in one from my
> wrecked silver 87. This replacement motor has been  sitting around for
> 4 years. When I start it up and rev it above 2000, the warning light
> and buzzer come on. It certainly has enough oil pressure when cold to
> close the 1.5 bar sensor. (I  checked it with an ohmmeter and verified
> that it is working.)
> I'm not 100% sure if the low bar sensor is working, but does that even
> make a difference with the dynamic warning system? The dynamic system
> was working fine with the previous motor.
> Any ideas? Ice pick to the cluster?
> Al Brase