I just swapped out the factory AM/FM/Cassette in my 98 taco 2.7L reg cab 4x4. It went pretty smooth but I had some questions about the wiring. Plugged into the back of the factory unit are two plugs, a wide and a small plug. The wide one has most of the wiring, but the small plug has one wire coming out of it. I believe it is white with a green stripe but I could be mistaken. I cut the wide plug off and wired up my new Sony head unit, but the small factory plug with the one wire remains. My new unit works correctly as far as I can tell, but I wanted to see what the other small plug with the one wire was for. Any ideas?