Thanks Ray for the link on the wiring diagram and confirming my code. I wasn’t sure which was the preferred function to initialize since wiringPi had three (wiringPiSetup, wiringPiSetupGpio, wiringPiSetupSys) but the first one I tried worked so I ran with it. Also, it was easy to solder a couple jumper wires to the board to use the relay’s output. That was clearly marked on the board. Nice touch having the +5V power and ground breakouts on the board conveniently located an inch away too. Just waiting for the snow to melt now!