I have an 88 convertible. when the signal is on and flashing and you depress the brake the signal goes off. This happens left or right or hazzard. It only stops working when the brake is pressed. any ideas??

 

do the brake lights work?

 

Have you made sure the right bulbs are installed? Your failure may be due to the brake light drawing all the power, or check for rub through of the insulation on the back side of the lamp holder. You may be shorting through that to a different ground when the brake is applied