I have a 2006 Range Rover Sport auto 4.4. A couple of weeks ago, the truck started to act up. I was headed home from work, it was still day light out, so I didn't have to turn on the lights. I didn't notice the issue until it got dark outside. When I turned on the headlights the truck wont go into the next gear. The engine would just rev. around 1-2 range. I turned off the headlights, and the truck is able to go into the next gear, and rides fine. I'm able to drive with the headlights on if I change over to the M/S sport mode. So I'm thinking when the headlight is turn on, its causing some kind of short/ power lost with the transmission. Maybe there's not enough power, maybe the battery, or alternator?? So I first decided to replace the battery, and I also notice the negative cable had some corrosion, and I ordered one online, and replaced the negative cable. It didn't fixed the issue. I then replace the alternator. It also didn't fixed the issue. I notice the back brake lights was also not working correctly. The 3rd rear light was also out, and the two brake light stayed lit, even when you stepped on the brake. So I decided to take the truck to an independent Land rover shop to do a scan. With the scan it had a few issues that came up. The shop stated it that I had a faulty brake light switch. The switch threw out 22 codes, and the shifter looks to be stuck on Neutral and Drive. They recommend replacing the brake light switch first, and the shifter will eventually needs to be replace. I replace the brake light switch, and the 3rd brake light housing. All the brake came back, and worked fine, but the issue with the headlight was not resolved. I replace the shifter, and that didn't fixed it also. I'm at a lost, my last resort is to take the truck back to the land rover shop, and have them work on the truck. Could it be a solenoid issue, relay, fuse??? Anybody else come across this ?