Driver Side Door Key Lock and Unlock Switch Circuit: Description

WARNING: This page is about a different car, the 2008 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.

The Front door key lock and unlock switch LH is built into the Front door lock motor LH. When the Front door key cylinder LH is turned to lock all the doors using the key, there is continuity between terminals L and E of the key lock and unlock switch. When the cylinder is turned to unlock the doors, there is continuity between terminals UL and E. Terminals L2 and UL3 of the main body ECU are connected to the door lock motor, and door lock/unlock request signals (by key) are input to the main body ECU. The main body ECU constantly applies voltage to terminal L of the front door lock motor LH via terminal L2. When the front door key cylinder LH is turned to lock all the doors using the key, current flows from terminal L2 to terminal L. The main body ECU also applies constant voltage to terminal UL of the door lock motor via terminal UL3. When the door key cylinder is turned to unlock the doors using the key, current flows from terminal UL3 to terminal UL.