1992 mitsubishi lancer evo jdm

Greetings. Just found this site and it looks like a great resource. I didn't find anything to match this car so 1st post. My son bought a 1992 Japanese Mitsubishi Lancer and we attempted to replace the factory stereo (Mitsubishi MB876828) yesterday with a Pioneer unit that has USB and allows him to control his ipod with it (sorry I don't have the model # right now). The wiring harness had no real color codes on it as they were all white with some brown. We cut the old connector and by trial and error figured out the speaker cables and via my volt meter figured out battery, ACC and ground. Everything seemed like it was going to work out except we had a couple of extra wires left over (which I think was maybe illumination and something else as they were not connected to this deck which was previously in his Integra) plus one wire that had a plug connector on the end similar to the antenna cable that I wasn't sure what is was for (maybe it powers the antenna?). At any rate we put it all back together and thought it was working ok until he drove it later and realized he didn't have any dash or taillights. The police helped him discover that. We checked and the fuse was blown and when replaced it blows as soon as the lights are turned on. So we took the dash apart/removed the stereo and replaced the fuse and now the lights are working again. If we hook it back up fuse blows. Tried connecting that wire with a plug on the end to gnd and it seemed to work until we hooked the stereo back up. Now as I'm typing this I'm think maybe I'm missing the point with this connector which is kind of like a banana plug for lack of the proper term so it probably needs power to the center and gnd to the outer case? But if my hunch is right then if it just sends power to the antenna it shouldn't be causing me all these issues should it? Question is does anybody have any experience with a car like this? Since this is a JDM car do you think I should see if I could find a connector replacement kit for this car at CDN Tire or something instead my DIY wiring? Sorry for the ramble. TIA.

OK, the extra lead was probably a Vehicle Speed analogue Signal (akaVSS) panel lights may have ben running through the original head unit as a GROUND signal, suggest check with original head unit. Also seperately ground the new head unit , disconnect the suspect wire and then see. One last thing as pros (OK I don't do much radio fitting any more) we ALWAYS use Interfaces when we can, it saves an awful lot of time and trouble.

It did turn out to just be a bad ground connection (per my son who says it's working now and with his new found knowledge is helping a friend who just so happens to have a similar problem with his Eagle Talon!). I hear yah on the kit as well. I did find one which would have certainly helped with the wiring layout. Thanks for the reply.