Black 2019 Ford F-150 driving on a coastal road.The Ford F-150 is one of the most popular and best-selling vehicles in automotive history (despite being dethroned by the RAV4 in 2025), so there's a good chance that someone reading this has one sitting in their driveway or garage right now. As such, you might want to get a little more information when working on your Ford or trying to diagnose a problem. A little extra data never hurtThe F-150's test function allows you to check the functionality of your tachometer, speedometer, oil level and temperature gauges, and all the dashboard lights. This functionality might come in handy when trying to pinpoint some of the common problems that might occur with the F-150.Additionally, you can monitor your coolant and transmission fluid temperatures more accurately than the gauges on the dashboard. The battery voltage indicator is also tremendously useful. Now, you can access most of these numbers by using an OBD-II scanner, which isn't super pricey, but it's still convenient that Ford included that feature in the truck's software itself for when you need it. Overall, a little bit of extra data never hurts, even if your truck is running fine. For gearheads and wrenching enthusiasts who like to get a little more granular with car care, diagnostic and testing modes, and the data they provide, are worth their weight in gold. Want the latest in tech and auto trends? Subscribe to our free newsletter for the latest headlines, expert guides, and how-to tips, one email at a time. You can also add us as a preferred search source on Google.