Thanks to all replied to my previous post about strange blinker problems. I've narrowed down the symptoms thus posting a new post. 
My 90gl auto has blinker problems. 
The left blinker blinks properly until the brakes are applied, then the taillight blinks the brake light rather than the blinker. This only Occurs on the left side. 
With the flashers on, they work fine, until you apply the brakes and the left taillight will blink the brake light. 

I have no idea where to start. 
I replaced the engine room grounds last week, though its possible I did a bad job. 

Any ideas?
-craig