So looked at your schematic, you need to verify that you have clean power to the power showing as " Cab Switched Power" on the top of the schematic. There is a 5 amp fuse in the middle of the schematic. The Electronic Trans Control Module has Pins 1=2 that are Battery power. Bottom of the Module Pin #18+ 35 are both grounds. Fuse E is 3 Amps and needs to be checked. One of the other pictures you posted had a bunch of relays, one of which is Cab Power Relay. All of these things listed need to be checked back to battery positive or negative . I made myself up a set of leads to be able to rremove the relays and test them individually to find out if they can handle a load like 5-10 amps without dropping out. If they don't work when off , they definitely won't work when on the machine. Lots of things to test. Simon C