1991 Buick Regal Left Blinker Doesn't Work

Since the light comes on. But doesnt blink, could be the blinker side of the bulb, try the bulb first. Then the relay ( under thedash, on the fuse panel). Usually if the bulb is burned out, the dash indicator blinks very fast to let you know you have a problem. Some bulbs have 2 elements- like brake/tail lights, so that the tail light stays on when you hit the brakes. If the bulb that isnt blinking, has 2 elements, likely that's the problem. Bulbs and relyas are relatively cheap and easy to do.