Sure, the easiest circuit to check will be the brake lamp circuit. At the turn signal switch you will see an all white wire. You need to check this wire for 12 volts with the brake pedal pressed. You should see voltage at this point. The next wire will be the all yellow wire. This should also have 12 volts to it with the brake pedal pressed. If there is voltage at the white wire, but not at the yellow wire, then I would recommend replacing the turn signal switch for sure. The turn signal switch itself is serviced as a complete unit with the turn signal lever and all. To access the wiring, you will need to remove the steering column trim covers. Here is where this switch is located. Feel free to contact me with any questions!