Radio wires

[Rawze]

some factory radios have an input for qualcomm device, so that the sound will come through the speakers above the sound of the radio. It could be that.

However: you mentioned that it is a green and yellow wire. It is quite common for devices to have Green and yellow pair of wires for the CAN+ and CAN-, J1939 connection. Roughly 2.5~ish volts or thereabouts on one (or both) wires when measured would also point it in this direction too.


Only way to find out for sure is to get the cab wiring diagram for your make/model truck and look it up. Last thing someone needs is to make an assumption and fry things.