Q: where is the door lock relay for 2013 toyota corolla located

The door lock relay function is built in to a multi-function "integration relay". The integration relay is in the dash to the left of the steering wheel. Note that if you are working in the area of the dash/steering column, you must disable the airbag system, per the instructions in the Factory Service Manual. Many tests have to be performed to condemn the integration relay. It is much more likely there is a broken wire, high resistance connection, bad terminal or faulty ground. Obviously, you want to have a conclusive diagnostic prior to potentially wasting time and money replacing parts. If you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an electrical circuit/component diagnostic and the responding certified mechanic will get this malfunctioning door lock issue resolved for you promptly. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.