If it's wired the same way the one I installed in my '89 was, the changer has a direct fused connection to the battery. While I haven't personally encountered the problem you reported, I do recall reading that a power cycle has a pretty good chance of clearing it. However, you'll need to do some wiring detective work to accomplish that, unless you just decide to disconnect the battery. If I were trying to deal with this, I'd probably just pull the ground off the battery for a long ten-count and see what happens.