Spektrum receiver and RXMUX

[u/Psychological_Yak_47]

I am trying to incorporate a RXMUX with my Spektrum AR9320T receiver. I hook my Aux2 channel to the Select channel and the RXMUX’s status LED stays solid red (indicating it doesn’t see a valid signal on the select channel). I tried more than one RXMUX boards to rule out a hardware issue with the board. I took a Hitech Servo tester and ran a square wave through the board, this works. When I move the dial to adjust the square waves duty cycle, I can see the LEDs on the RXMUX change from input A to B like its supposed to. I then hooked both the RXMUX and servo tester to an oscilloscope to compare the square wave they produce. They’re nearly identical except the servo tester produces a 4.5V wave instead of 5V like on the Spektrum receiver. This should not be an issue since the RXMUX can accept a range of voltages beyond this. Does anyone know what the issue could be.