Where is "C" wire on Honeywell 8043F1036
According to the wiring diagram I found, typical wiring is as follows.




1 END SWITCH (To circulator or another valve)
2 END SWITCH (To circulator or another valve)
3 TH/TR (Thermostat and Transformer)
4 TH (Thermostat)
5 TR (Transformer)


You'll have to verify this is how your valve is wired, but it looks just like the diagram to me. If this is how it's wired, you should be able to connect the c wire to the TR (5 in your image) terminal on the valve.