I bought an LX470 a few months ago and the seller said it needed a nav DVD (showed "No Disk Detected"). Turns out the DVD was in the player the whole time, so thinking it was a bad DVD, I tried a new one from a dealer. Still no luck. Clearly I needed to replace the player but alas it still shows "No Disc Detected." When I replaced the unit, there were 3 plugs and one empty slot (closest to passenger side). Am I missing one of the plugs? Anyone else solve this riddle? Thanks.