Support

Last updated 3 October 2026

Contact

supportmerclight.app. We aim to reply within a few working days.

Before you write

The app has a built-in help section (Settings › Help & FAQ) and can export a diagnostic log with identifiers masked. Attaching that log makes almost any problem faster to diagnose.

Common issues

• The adapter will not connect. Turn the ignition on (the engine can stay off), confirm the adapter is seated in the OBD port, and grant the Bluetooth permission.
• "Headlight ECUs not identified". Your vehicle's lighting modules are not ones the app recognises yet. The app checks with our server for a newer mapping automatically.
• Effects will not play after buying. Connect to the car and play a paid effect. With Lifetime, the car is added to your account then, with no limit on how many. With a pass, the first car you play a paid effect on becomes the pass's car, and it cannot be changed. Every effect needs an internet connection when it starts. If it still refuses, use Restore Purchases.
• Which adapters work. We recommend MBito OBD, vLinker BLE and KONNWEI Bluetooth LE adapters; they are the ones we test. Other ELM327-compatible Bluetooth LE adapters may work, but very cheap clones can be too slow for the fastest strobe patterns.

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