Why are my dome lights randomly coming on?

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. My usual thought when it comes to the dome light coming on randomly is that a door is being seen as open - when it's not. But you're saying there is no door ajar light on - so that seems to eliminate that idea. The next thought I have - is there an add on aftermarket alarm installed? I suspect any wiring that may be tapped into the factory wiring could cause unusual electrical behavior. So, check for that. Lastly, the 2008 F150 has an instrument cluster module (IC) and a vehicle security module (VCM) - both of those systems can be connected to via a diagnostic tool able to check body related modules. The modules can be checked and components accessed to test them with a proper diagnostic tool. After this, you can see if lights are being commanded, or if they are not and they come on anyway. It is likely helpful to have a shop near you weigh in. See below to find one. https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.