electrical problem
 

hi there im havin trouble with my s14 it was broken into there a while ago when i was away and the ****ers broke the barrell, my father had it replaced with a nissan micra barrell but she keeps konking out even while driving then all i have to do is turn the key and shes kicks back in straight away.... would this be down to the barrell or would it possibly be a relay??? also the reverse lights wont come on while in reverse no i replaced the bulbs but they wernt blown is there anything i can check??