Infra-red keyfob self test mode

To test the transmit / receive LEDs built into the keyfob, point it at a reflective surface, about 10mm away, and hold down the “unlock” button. After blinking the LED a few times it will light up continuously to confirm that all is well. To verify that it really did do the test, try it again without pointing it at a surface (just point it into space somewhere), and the LED stays unlit after the initial blinking.