If the box is mounted to the fridge’s frame beside the compressor, it’s most likely a mechanical defrost timer. A photo or component label would be needed to confirm that. “ABS” identifies the cover’s plastic; it doesn’t tell you what’s inside.

A mechanical timer uses a small motor and gears to switch the refrigerator periodically between cooling and defrosting. Rapid ticking while the fridge still cools suggests a noisy timer mechanism or a loose cover vibrating with the compressor. Feeling vibration in the cover won’t tell you which is causing it.

A compressor start relay is another possibility, especially if the box attaches directly to the compressor’s electrical terminals. Clicking from failed starts usually comes with interrupted compressor operation and poor cooling. A steady four clicks per second is less typical of that fault. [GE’s clicking-noise guidance](https://repair.geappliances.com/resources/faq/article/why-does-my-fridge-keep-clicking-on-and-off)

To check it:

- Unplug the fridge before removing the cover, since the enclosure may contain mains-voltage connections.
- Check for loose mounting screws or a cover touching nearby metal or tubing. The Y-shaped screws likely need a tri-wing bit.
- Read the label on the component inside. Use it and the full refrigerator model number to confirm what the part is.
- If the timer itself is noisy, replace the complete timer with a confirmed compatible part. If the housing is rattling, fix its mounting.

Don’t bypass the timer, leave its electrical cover off, or pack cardboard inside it. A photo showing the box and its mounting would help distinguish a defrost timer from the compressor’s starting components.