how to change vacuum pump on 2.5 gas engine and were is it located

A vacuum pump is often on a diesel car to operate the brakes. Do you mean the secondary air pump? They often fail due to water getting in them and can cause the relay that operates it to fail as well. 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