OK, unsure if this just started or has been doing this all along but when the turn signal either left or right is activated it flashes but apply the brakes and it goes solid, let off brake and it resumes flashing, I cannot make out on the wiring schematics we have what is crossing....anyone?
Sounds like the brake wire is crossing with the turn signal wire somehow. I had this problem for a little while and it self corrected, but I've also rewired a lot of the car including changing over to modern fuses. If I remember correctly the turn signals are white with a light blue stripe, and the brake lights are green. (May or may not have been a stripe on that.)
the brake lights got to the turn signal switch. thats so the turn signal will cancel the brake light on that side. it sounds like its some how its not canceling it. odds are its the turn signal switch that has the problem.