where do you locate the evap solenoid on an 04 honda civic lx?

it should be located on the evap canister.

Two wires on evap solenoid black/yellow and yellow/blue except GX model. Canister is in the back of the car canister purge valve is in the engine compartment under air intake housing driver's side. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online