The Throttle position LED should be on when your foot is not on the pedal and
then when you push it all the way to the floor.  If it is not on before you
touch the pedal then either the idle switch is missing (happens) or not
adjusted properly.  I have these if you need them (looks like a microswitch
used in the aircraft industry for shutting off flap motors at full travel,
etc).
Bentley has the proceedure for adjusting this properly with a multimeter or
using your digitool.

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
Fax   (856)-327-2242