option 1. plug in oem radio and it will work. option 2, go into the dash where the radio used to be. look for the radio harness, big white plastic connector that fit into the original radio. attatched to it should be a green plastic harness, this is the "security harness" on there you will find two pins that you need to connect to get the dome light to work again, let me find the diy real quick.
Edit* well i cant find that stupid diy, anyone else know where it is?