I have a Trane electric furnace and I am only getting 15 volts at W on the thermostat. Both Y & G are both getting 24 volts so I can only assume I am losing one leg of power on the W circuit. What I am not sure of is how to track it down so I can fix it. The heat will not come on. Both the cooling and the fan will come on if I switch the thermostat to cool or fan only. I have been into the air handler to investigate and was surprised not to find a circuit board inside. The unit is a 2010. Any help would be appreciated.

Are you checking at the thermostat itself?

Are you checking at the thermostat itself?

It is a digital thermostat, so the actual thermostat is removed, and I am taking the readings on the on the thermostat mounting plate.

You are measuring between R (red) and the other terminals?

You are measuring between R (red) and the other terminals?

Yes

An open ciruit should give you a full 24 & a closed circuit should read zero. Sounds like a drain on the white wire somewhere. If there are any unused wires, swap one for the white on both ends. If you still get the same 15 volts, it would seem the drain is in the appliance.