i think 2000c indicates an open circuit to reflect the negative temperature coefficient of ntc thermistors (pt100 may be the other way around as they're positive but been a while since i used the pt100 daughter board so don't quote me on that)
could still be suspect wiring but could also be you're using the wrong input? show your wiring and config?
edit: wasn't sure if the maestro had a vssa fuse, but seems rev 1.0 does at least, if it has failed then that would also result in all inputs showing 2000C, so check the fuse.
