Transmission Temperature Switch

Gear Selector Switch Circuit:

Purpose:
The temperature switch allows the ECM to lock the Torque Converter Clutch (TCC). The application of the TCC makes a positive mechanical link between the crankshaft and transmission input shaft. Under less hydraulic stress, the hydraulic fluid can circulate and cool.

Operation:
The transmission must be in fourth gear for the temperature switch to apply Torque Converter Clutch to cool the transmission fluid. The temperature switch is normally open. As the temperature increases the bi-metal switches, allowing the ECM to control the TCC solenoid. The temperature switch locks at about 155°C (279°F) and unlocks at about 143°C (259°F).

Location:
The temperature switch is located inside the transmission.