Left signal won't work in 89 New Yorker

You haven't given enough information to rule out enough to say it's a wiring problem. You need to check for power and ground at the socket. Then diagnose based on your findings.

-Bruce

First question: Which kind of '89 New Yorker? The "New Yorker" (front wheel drive) or the "New Yorker 5th Avenue" (rear wheel drive)?

Does the left REAR blinker work?

DS

This the front drive. All the blinkers work even the side ones except the front left.

Probably a socket, wiring or ground problem.

DS