IM having elctricale problems when the car is.

Im having elctricale problems when the car is started for a little while why I have lights heat on the lights on dashboard goes dime and car shuts off the battery tested good the alternater was good and I just replaced the voltage regulatore and still having the problem the engine is a 1.8L egine know if it is the starter were is it exactly located? And also can a extornale gas pump mack it to that or would it be a starter? But when the parts store checked the battery they checked alternatore and starter with there computer and it tested good well my father and I actually took alternatore off I took the alternatore to store to mack sure and it tested good I cant understand what my electricale problem could be im lost on this electric thing my brother said since I put a brand new voltage regulatore on that the sylaniod on starter coulf of fried cuz I have hade this car for 5 years and never replaced starter yet plz help thank you very much