Couple thoughts. They show a dealer locator (not the dealer area). That’s got two in Sacramento and one in Phoenix. They might be worth a call. I’d be kind of surprised if they didn’t use a standard color of some kind. Red for power, white for ground, something for a memory, electric antenna, etc. clear across the line. If that doesn’t work, maybe a local radio repair guy could open it up and tell you what’s what. That would probably be an out of dash deal.
When you get it working, please post how it sounds. I’ve got a couple custom autosounds that have failed and I’ve been looking at Antique as a solution but their kind of pricey to take a chance on with no feedback.