York Furnace and A/C 2002 - wire cut.

I accidentally cut the wire from my thermostat to my furnace and after repairing the wire the furnace and a/c will still not work. Any ideas on what the problem could be? Thanks.

You may have overheated and ruined the 24vac transformer. This is the control voltage that energizes the controls of the system. Assuming you made good splices, verify you have 24vac available. An electronic thermostat might not have been happy, either depending on how the cut happened (it could have shorted things together). Note, many electronic thermostats have batteries in them...check yours to verify they are still good. On some, the batteries are only for backup, on others, they actually run the thing. A mechanical thermostat won't have that problem.

You might have tripped the circuit breaker, and there may be a small fuse on a control board inside the furnace.