What we want to work this time of year is air conditioning. The A/C on most new cars is controlled by the computer. Temperature control and where the air comes out is controlled by electric motors. When we change from vent, floor, or defrost, the motors are what move the doors. We do see problems with the motors. Symptoms are the air not coming out of the place where we set the controls or a clicking noise; some of these motors are hard to change. These circuits are protected by fuses.
The windows and door locks use fused protected circuits. The windows use a circuit breaker instead of a fuse. When we hold the up button to long, the breaker will reset the system. Window motors are inside the door panel and can be hard to change. We see some problems with the wiring from body to door. The door locks also work with the key fob. The key fob is a transmitter and the receiver is in the car.
Another important circuit is the windshield wipers and washers. The wiper system is protected by fuses. There is a wiper motor that is controlled by the switch and a module that controls the intermittent.
Lights are also a key system. Most vehicles have auto lights and daytime running lights. We need to know how these systems work so we will have on the tail lights when needed.