Carrier 58GS125-JA
I'm out of town and my wife just called me to say the furnace
Won't come on how can I troubleshoot this with her over the phone.

If the system is also equipped for air conditioning, set the thermostat fan selector to "on". If the blower starts/runs, this will verify that power supply is present. If it doesn't operate, check the basics first: 1) Is the thermostat set correctly? 2) Circuit breaker tripped or fuse blown? 3) Is the blower access panel securely in place? (There is an interlock switch located behind this panel. If the panel is loose, the switch may disengage, interrupting power to the unit.) Here is a link to a video clip of the operating sequence: http://www.youtube.com/watch?v=gI9UC_wE1_M .