I have a 2004 HSE Freelander. Every time I drive over a significant bump, the rear tailgate sensor would report that it was open, turning on all of the cabin lights. For now, I pulled the interior lights fuse because for night driving. I have an appointment to get it fixed, anyone know what's wrong or how much it'll cost?

 

I would try lubricating the latching mechanisms. Maybe it`s not latching completely allowing the door some play on rough terrain. That or it could be a stuck/worn out sensor that needs replacing. This probably isn't much help, but who knows. I'm sure it's something mundane and cheap. The labor fees will be the worst of it.