Recently got an 08 800. AWD isn’t working. Sprague carrier is aftermarket and good to go. Replaced armature plate. Resistance on coil is good. When I checked the volts coming from the dash switch to the diff via the 2 wire harness the voltage was all over the place and never got above 9. I’ve searched for a while and I’ve seen all the YouTube videos but never found an answer. Bad switch? Bad ground?