I have a problem where the starter relay “flutters” when I hit the start button.
A failing starter motor can cause a relay to “flutter” or rapidly click. This fluttering occurs because the starter motor, when failing, may draw an irregular amount of current or not enough to maintain the relay’s activation. Here’s how it happens:
- Increased Resistance or Fault: If the starter motor has increased resistance due to wear, damage, or an internal fault, it may not draw enough current smoothly. This can be due to bad bearings, damaged windings, or other mechanical issues within the starter.
- Insufficient Power: The irregular or insufficient power draw can cause the relay’s electromagnetic coil not to hold its armature consistently in the closed (on) position. As a result, the relay may rapidly open and close, leading to the fluttering sound.
- Voltage Drop: A failing starter can cause significant voltage drops in the circuit. When the voltage falls below a certain threshold, the relay may not have enough power to stay engaged, causing it to rapidly switch on and off.
- Battery Condition: It’s also worth noting that a weak or failing battery can exhibit similar symptoms, as it may not provide enough power to keep the relay engaged when the starter motor demands a high current.
When you hear a relay fluttering in the context of starting a vehicle, it’s a signal to check both the condition of the starter motor and the battery, along with the relay itself and connections in the starting circuit. Proper diagnosis often involves measuring voltage drops, checking for clean and tight connections, and possibly testing or replacing the starter motor if it’s found to be the cause of the issue.
I have a new Rick’s Starter Motor on order. The battery appears fine, although I don’t yet have a tester (on order). All the connections look great to the eye. I have not done any actual continuity testing yet.