You can get the switch from almost any parts store. There is the remote chance that the end of the pivot is broken. That is another story. If that is the case, it may be easier to replace the column than the pivot. You will not know until you get the wheel off.
You need a steering wheel puller, locking ring tool, an ice pick, and a clip ring pliers. The steering wheel puller, and locking ring tool are available as loaners from most parts stores. You will probably have to buy the clip ring pliers, and an pointy steel rod will work for a pick. A pair of needle nose pliers would make removing the clip ring for the lock ring easier as well. Be careful to not bend the wire ring excessively.
Once you have it apart down to the switch, you can check the pivot end. If it is good, install a new turn signal switch and you are good to go.
The turn signal switch has a wire bundle on it, that must go through the column. You must remove the translucent cover on the bottom of the column to get the wires in and out. A piece of coat hanger wire will help you feed the new wire through the column.
If the pivot end is broken, it is probably easier to replace the whole column, and will take a lot less time and effort. The only way to get the part, is to disassemble a donor column. 91 columns are unique, 92-3 columns are the same, and 94-96 columns are the same (except the 96 Impala). You can use any newer column on an older car. You can paint the bezels to match if you can not find one the correct color.
The FW column is a little longer than the B body column, but will bolt up to the B-body. The intermediate shaft between the column and steering box may not extend far enough to engage the D tube firmly. That would make the steering sloppy, but it will work.
1991 OCC 461 (.030 over 454) BBC, 3.23 posi, flash to pass, drop spindles & springs, Impala rims, Hydroboost, Recaros, MOMO/wood SW w/QR, custom wood shift knob, Pioneer DEH P77DH
1992 OCC now with 5.7 tbi, DEH P77DH
For a parts list, check https://www.impalassforum.com/vBulle...ion-parts.html