What are the symptoms of a faulty starter relay when starting the engine?
3 Answers
Power supply issues such as severely depleted battery, sulfated or short-circuited battery plates, poor contact between battery terminals and cable clamps, or loose connections in the starting circuit can cause starting problems. Below is an introduction to relays: 1. Introduction: A relay is an electrical control device that causes a predetermined step change in the controlled quantity in the electrical output circuit when the variation of the input quantity reaches specified requirements. 2. Principle: It is an electrical device that makes the controlled output circuit conduct or break when the input quantity (such as voltage, current, temperature, etc.) reaches a specified value. 3. Characteristics: A relay is an electronic control device with both a control system (also called input circuit) and a controlled system (output circuit), typically used in automatic control circuits.
Last time my car's starter relay failed, there was absolutely no response when turning the key to start the engine—it didn't even make a humming sound, as if the battery was completely dead. However, the headlights and dashboard were lit, indicating the battery was fine. Upon closer listening, there was only a faint 'clicking' sound, which indicated an issue with the relay's internal contacts. The relay acts as a signal switch, responsible for transmitting current from the ignition to the starter motor. If its contacts oxidize or the coil burns out, the current can't pass through, and the starter motor naturally won't engage. I tried tapping the relay box lightly, but the symptoms didn't improve. Later, replacing the relay fixed the issue. This problem is common in older cars, so it's advisable to regularly inspect small components in the engine bay to avoid last-minute repairs that could disrupt your trip.
In a hurry to drive to work in the morning, I turned the key to start the engine, but it seemed like it was asleep, completely unresponsive. The usual roar of the engine starting was absent, with only one or two faint clicks coming from beneath the dashboard. This is exactly what happens when the starter relay fails, as it controls the signal path to the starter motor. If there's an internal short circuit or disconnection, the entire system shuts down. Such failures can sometimes become more pronounced in cold weather, necessitating checks on related fuses or voltage issues. At the time, I had no choice but to call for roadside assistance, spending a few hundred dollars at the repair shop to replace the relay. Looking back, prevention is simple: during each maintenance session, have the technician test it casually to avoid such sudden incidents affecting travel safety.
