1991 Oldsmobile Cutlass Turn Signal

On some models you will need to remove the headlight bezel mounting screws and the bezel.
Remove the mounting screws for the lamp assembly.

After the screws are removed, pull the assembly from the vehicle.
Disconnect the twist lock socket from the lens housing.
To remove the bulb, turn the twist lock socket (at the rear of the housing) counterclockwise1/4turn, then remove the socket with the bulb; replace the bulb if defective.

To install:

Install the electrical harness to the back of the unit.
Position the signal assembly, then attach to the vehicle with the mounting screws. Tighten the screws to 54 inch lbs. (6 Nm).
Insert the socket to the back of the unit, then attach the headlamp bezel if removed.

What type of Cutlass do you have? Ciera, Supreme etc?

Okay see if these help a little better

Disconnect the negative battery cable.
Remove the two screws at the top of the assembly and pull the assembly forward.
Disconnect the electrical connector by opening the tab.
Remove the bulb and socket assembly.

To install:

Install a new bulb in the socket.
Position the socket assembly into the housing and tighten the two retaining screws.
Connect the negative battery cable and check for proper operation.