Tow Lights and Prevost

[Kuhlsport]

I got the RAM wired up today without any hassles. I installed the separate bulb set from Blue Ox in the tail lamp housings. Before I pulled the wire loom up to the front bumper for termination at the base plate, I tested my work by simply touching the wires to the correct spades on truck's trailer socket. Everything worked fine. Will be interested to see how many wires feed into the back of the plug on the bus. If 5 I need to convert down to 4. If 4, then I should be good. What is the easiest way to determine which wire is which at the bus plug? Bus is stored 30 minutes away and have not actually looked at the Liberty end of this deal yet. I'd like to try to accomplish something without a call to Troy if possible. I owe that guy a case of wine already!