What is wromg when there is no oil pressure?

Check oil level, 1993 cars have a lot o miles on them and engines wear our. The oil light comes on just before engine damage begins. Stop driving and check oil level. If you have add more tan 1 quart, your engine is losing oil, either by a leak or oil consumption cause by worn rings, piston or engine bore.
Good luck

1993 Buick Park Avenue 3.8L SFI OHV 6cyl

The Horn Relay is located: Under hood, center, upper firewall, passenger side of blower motor, mounted in relay block.Here's what it look's like Ken. Duralast Relay Radiator Cooling Fan Motor 19272 1993 Buick Park Avenue...

On this websites you find fuse box diagram and description for Buick Park Avenue (1993)

Buick Park Avenue 1991 1993 fuse box diagram CARKNOWLEDGE

https://www.autogenius.info/buick-park-avenue-1991-1993-fuse-box-diagram

replace the oil pressure gage sending unit, it is a common problem with all GM oil pressure gages.

Change the oil pressure switch then try

Most likely a blend door issue inside the dash or a problem with the HVAC Control head.Hope this helps!!

1993 Buick Park Avenue. The overdrive shifts in and out on flat ground. It holds o.k. when in a slight pull up grade.

open the driver's side door and look on the sticker. It will show you what size tires to put on the car and the tire pressures.

My indicator lights aren't working can't find the switch to replace it, I have a 1993 Buick Park Avenue

The oil pressure switch is located next to the oil filter