Trunk Wiring problems of the 2009 Mercury Grand Marquis

I had checked the tire pressures prior to a road trip and found them at 38 psi. I reset the pressures to the spec of 33 psi. Shortly the tire monitor came on and signaled a low tire pressure. I rechecked and they were ok. During my trip the light would keep coming on and I tried to reset the system to no avail. On my return, the power door locks kept malfunctioning. The door key pad would work sometime for both the doors and trunk. The next time they might not. The door switches on both passengers and drivers side would work sometimes. With both the tire pressure system and the door locks acting up and creating a nuisance, I took the car to the Ford dealership, two river Ford in mount juliet, TN. . The found a shorted wire in the harness going to the drivers side module that coordinates most of the safety systems on the car. There was no fire in my case, however, there could have been. I did receive a bill for $272. 30. My concern is that Ford apparently does not accept any responsibility for what I consider a safety issue whether it was caused by poor system design on the harness layout or electrical current exceeding the wiring capabilities. Was it caused by excessive movement in the harness or was it current going through the wires as I tried to reset the pressure monitoring system 20-30 times. I am more then interested in knowing how many similar failures Ford has had in the Grand Marquis and the Ford crown vic.