Nate beat me to it but the flash pattern has been changed since 2009:
- Fast Blink (200ms on / 200ms off) - System error: No driver's station communication, bad cRIO Image, bad team ID, extensive communication errors.
- Steady on - Autonomous
- Short off - (1500ms on, 100ms off) - Tele-operated enabled
- Fast-Slow Blink (200ms on / 900ms off) - Low battery (<12 Volts) and system disabled either by system watchdog, user watchdog, or Driver's Station set to disabled
- Slow Blink (900ms on / 900ms off) - System disabled
And of course if the light is off completely either the cRIO could still be booting or the light may be wired wrong. If the RSL has a different flash pattern that the LED on the Digital Side Car, make sure there is a jumper between La and Lb on the light.