Has anyone ever replaced their instrument cluster with a junkyard one? What happens? The manual says irreparable damage to the cluster can occur if plugged from one vehicle into another. The VIN and odometer are programmed but it says the cluster can also figure out everything. The reason I ask...

My 07 v6 3.7 jeep commander is having cluster problems. When driving the speedometer and Rpm gague would look as if its resting (going up and down) but while the car is driving, this happens 15 times or more in a 30min drive. When it go's hay wire it some times shuts off the high beams it shuts...