I have a cheapo I got of Amazon for $20. It shows you a number, look it up online, then if you can fix it. It also allows you to cancel bogus service lights that pop up from time to time. Basic, no batteries, no apps, plug an play.
2017 SLX 195RB
2014 Jeep Grand Cherokee Overland, gas 3.7 V6
Andersen WDH hitch
Dometic Milenco Aero mirrors