My Road Runner is acting like it's bad (tries to start, then won't do anything once the ignition is selected to 'on'). How do I test one to see if it's bad;i.e. how much resistance should I be reading with a meter? And the local auto parts store only sells a 4-terminal piece & mine's the 2-terminal type that came in the Mopar Performance electronic conversion kit. Can I interchange the two?