That depends on which engine you have, which you failed to mention. Go to the link below and pick the correct engine.
Behind the harmonic balancer (dampner) that is located behind the crankshaft pulley.
price on replaceing ball joint 1993 cutlass supreme
transmission
its in back valve cover at fire wall i removed the plenum from the intake manifold to get at it.
You have to put it in the overflow tank.
With money take it to someone who knows.
Nee more info cutlass supreme or cutlass ceira which engine 3.1-- 3.8-- 3.3-- ????? Oldsmobile cutlass ceira 3.3 liteer engine
The brain or ecm is located on passenger side, underneath glove box. Remove a few 6mm screws and there it is behind plastic cover.
The most obvious thing to check when a 1991 Oldsmobile Cutlass Supreme won't start is to make sure that the vehicle has gas. You should also check the battery. If the car clicks when you try to start it, it is likely the alternator.
The horn relay on a 1991 Oldsmobile Cutlass Cierra is located on the passenger side firewall inside the engine compartment. It is just to the left of the blower motor assembly.
This information is listed in your owner's manual. Don't have one, get one. Dealer, salvage yard, e-bay, Google Search. I have a 92 Cutlass, the glove box is a molded piece of plastic that can be pulled out to reveal the fuse panel.
its in the gas tank u godda take the tank off