I turned on my 2007 Mercedes GL450 in my driveway to warm it up and 1 minute later the horn continually went off. I turned the car off and the horn continued. Smoke began from the passenger rear tail light, then a flame. 911 was called the moment we saw smoke. Within seconds the back seat was engulfed in flames and then the entire car. The flames were as high as my 2 story home. There is nothing left of this car. The amount of broken glass from all the windows blowing out down my driveway is unbelievable.

- Burlingame, CA, USA

Horn starts honking by itself. Will sound for 30 seconds or more and then stop. Otherwise the horn does not work.. horn continues to randomly sound while driving. Very unsafe as it startles other drivers. Took to dealer who diagnosed the problem as a broken horn sensor. However to fix, they said they needed to replace the steering wheel. Total price is $1300 with labor. At this price it will be a while before it can be fixed. This appears to be a common problem with this model. A google search turned up several similar complaints on various forms. At the $1,300 cost, there must be several Mercedes gl 450 's driving around with faulty horns.

- Irvine, CA, USA