What is the likely problem if you wired the Down Direction and Final Limit switches but the car only runs up?

If the car only runs up and does not respond to the down command, this suggests a potential issue with the wiring or functioning of the Down Direction limit switch. The Down Direction limit switch is responsible for signaling to the control system that the car has reached the lowest level or has received an instruction to move down. If this switch is incorrectly wired, it may not send the appropriate signals to the motor control system. As a result, the system may fail to recognize the command to move down, causing the car to only move upwards.

This issue highlights the importance of correct wiring in control circuits, where each switch must correctly connect to its intended input in order to ensure proper operation. The other choices represent different types of potential issues, but in this specific problem, the wiring misconfiguration of the Down Direction limit switch is the most plausible cause for the behavior observed.