On the 6.0L Denali Yukon, evap purge solenoid is located in the engine compartment on top of the engine near the throttle housing two wires on it dark green white and a pink wire on it. 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