Missing JUST Brake Lights on 89 Cutlass

I have recently re-installeed the rear light covers and as soon as those were in, the rear brake lights stopped working. Checked fuses, wires, bulbs, checked for voltage across the wiring harnesses, and still can't find a problem. I thought it might be the turn signal switch problem I've read about, but the center brake light still comes on.

Any help would be great.
Thanks

I have recently re-installeed the rear light covers and as soon as those were in, the rear brake lights stopped working. Checked fuses, wires, bulbs, checked for voltage across the wiring harnesses, and still can't find a problem. I thought it might be the turn signal switch problem I've read about, but the center brake light still comes on.

Any help would be great.
Thanks

Try applying pressure on your turn signal indicator by pulling back slightly as if to turn on the bright lights, then hit the brakes, if they come on when you do this, it's the turn signal switch that breaks on this model, you'll need to replace the switch and you'll have it.