When I first got my '91 Carat, a couple of months ago, I noticed it had a
brown wire attached to a screw on the throttle body.   On investigation , I
found it was the wire to the high pressure oil switch.
I reconnected it to the switch and of course the light and buzzer started
coming on when the oil was hot, but not consistently.   It may have been a
bad switch.
I replaced it with a new 0.9 Bar switch as this seems to be the consensus,
and have had no more trouble since.     I use Castrol 20w -50 but I have just
changed to Mobil 1 15w-50.

So.... it has been done but I for one prefer the switch to be operational.

cheers,
Steve Cotsford
Columbia SC