No heat only A/C all the time, code f 13

The sensor is located behind the upper dash cover on the right side. Start by removing the vents from the trim cover, a thin screwdriver at one end and pull them out, Then remove the screws at both sides of the trim pad. The pad then lifts off. That gives you access to the sensor for testing or replacement. There is a TSB on them but not for a total loss of heat but for temperature drifting. That relates to the last image showing the sensor needs to be inside the tube to the aspirator and not outside it. As you are not getting heat it sounds like the sensor or wiring has a short in it. If the sensor had failed open it would only give you heat as it would think it was 40 below zero.