I purchased a wifi thermostat and cannot located the common wire. My unit is old and is a Coleman 70 with no terminals inside labeling the wires. wiring diagram wires

As you can see in the second image, there is a blue wire that is not being used that goes to my thermostat. I am trying to use this as a common wire, I am just unable to determine where this wire connects to.

THank you for the help.


I've highlighted the C wire for you in the schematic.

Highlighted c wire

And in the actual wiring

Highlighted c wire

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