1988 Mustang Automatic to manual transmission swap but my back up lights will not work. I installed a Tremec 5 speed. Has anyone had this problem? Thanks for any suggestions.

ok i have a 89 fox with a 5.0 and a t-5 in it. i just smoked the t-5 at the dragstrip. i looking in to fixing it but is it worth it. i am new to the mustang stuff i am a mopar guy that just sold it for a fun little mustang and i really dont know much about this car. but like i said my trans is...