What issue might occur if a turn signal only operates for the right turn?

If a turn signal operates only for the right turn and fails to activate for the left turn, it suggests a problem specifically related to the circuit responsible for the left turn signal. A defective bulb is a viable explanation for this issue. If the bulb for the left turn signal is burned out or malfunctioning, it will not illuminate when the left turn signal is engaged, leading to the observed problem. A bulb that works for one side and not the other is a common fault that can easily be overlooked during troubleshooting.

In this context, while other electrical problems like a faulty relay or wiring shorts can affect signal function, they typically would result in either complete failure of the turn signals or the malfunctioning of both sides, rather than just one. A dead battery would generally cause all electrical functions to cease, not selectively impact the turn signals. Therefore, focusing on the bulb offers a straightforward solution for diagnosing the specific issue of the left turn signal not working.