To add to the point above: scanners are helpful, but I actually think youll save more cash checking high-wear items like tires first. These heavy rigs chew through Pirelli Scorpion Verde All Season 285/45R20 tires fast. If the tread is low, use that to knock a grand off the price. Also, if the brakes are shot, grab a PowerStop Z23 Evolution Sport Brake Kit and do it yourself to avoid the dealers markup.

TL;DR: Inspect for sunroof leaks and suspension wear. Check the footwells for any dampness because clogged drains ruin the MMI modules. It's a common, expensive failure. Also, look at the front lower control arm bushings for tearing. Honestly, using a tool like the Autel MaxiCheck MX808S Diagnostic Scanner is the only way to be sure there arent hidden electrical faults lurking.

I've been very satisfied with the 2018 model, and it works well for heavy snow. Specifically check the water pump and thermostat for leaks, as those are common failure points. Using a OBDeleven NextGen Bluetooth OBD2 Scanner helps scan for hidden suspension faults. Its a reliable way to verify the air bags are holding pressure correctly... no complaints with mine yet.