Motorcycle Questions? Ask a Mechanic.
No, the brake light circuit is not linked to the TSM.
The most common issue with that brake switch is not getting it properly aligned when re-installing the halves of the switch housings. The switch is easily pushed backward by the brake lever. This should result in the brake light staying on. If the brake light is staying on then this is most likely the problem. If the brake light is off and just doesn't brighten then the problem is in the wiring as mentioned below.
The most likely cause of your turn signal (and possibly the brake) problem is a wiring issue in the right side handlebar harness. These problems typically can be traced back to the last common spot that modifications were made that may effect both circuits and the handlebar harness would be that spot.
I hope this helps. Please let me know if you need further assistance. Also, please leave a positive rating for my service today. Thanks, P.J.