The torque converter clutch solenoid is a normally open exhaust valve that is used to control torque converter clutch apply and release. When grounded (energized) by the PCM, the TCC solenoid stops converter signal oil from exhausting. This causes converter signal oil pressure to increase and to shift the TCC valve to shift into the apply position.
The brake switch is an input to the PCM, and the PCM directly controls the TCC apply based on the brake switch status.
Important: The TCC solenoid resistance should be 20-40 ohms minimum when measured at 20°C (68°F).