I just bought an 89 Iroc last week.
Today I noticed when I step on the brake, both turn signals lite up.
Also some of the dash gauge light lite as well.

It is the strangest thing.
Anyone heard of this happening before?
I'm open to suggestions.

 

Verify good grounding at the brake lights. There may also be a problem at the turn signal switch. The dash lights illuminating sounds like a poor ground or cross connection somewhere.

 

Well I found what the problem was quite by accident today.
I replaced the tail light/brake light bulb and the problem disappeared.

After I realized the problem was fixed i measured the bulb with an Ohmmeter and found that the 2 filaments in the bulb were shorted together.

Just thought I would follow through this problem with the solution.

 

Thanks for the follow-up. That would be an odd one.