CAT 242D

I have a cat 242D with electric coupler that won’t unlock. I thought I had a bad switch but it’s not. I have 12V to the unlock wires only when the unplugged from the motor. With Wires plugged in and lock switch activated I have 12V power at lock wire. -1.9V at unlock. When the motor is plugged in and the unlock position in the cab switch is activated, I have no power and Ground is -1.9V on both wires. Unplug and activate unlock switch, I now have power on the machine side of the plug. I cut a spliced to verify operation and the motor works no issue. The system ONLY works in the lock position not unlock when activated from switch. Switch wires and the motor runs opposite direction smoothly. I’m thinking this must be a relay issue, can anyone shed some light on this? I replaced the cab switch today. Where is the relay located? Back of machine in engine bay bottom right? Part numbers? Thanks CAT0242DTDZT00248