You have no 12v to the thermostat. It is fed from 12v at the furnace. Assume you have an Attwood. There is a reset rocker switch on the furnace. To gain access, you would need to remove the furnace cover from the outside, about 8 square drive screws. Most likely you do not have a square drive so a #2 Phillips can be used.
__________________
Making a smooth transition to senility for over 70 years
2017 Freedom Elite 29fe
2015 Jeep Wrangler Toad
|