You need to trace the electrical circuit to see where the power supply comes from (a relay, a fuse). You need a wiring diagram and a good voltmeter. 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
If all your tests indicate the computer may be bad this company
have tested and repaired Chrysler computers for me.