Two problems related to brake light have been reported for the 2005 Ford Mustang. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2005 Ford Mustang based on all problems reported for the 2005 Mustang.
After heavy rain for a couple weeks. I was driving strait, in the rain on a city street. I noticed my radio turned off. Then also noticed my headlights and blinkers were also not working. After reaching my destination before it got too dark I stopped and tested all lights including brake lights. All of the exterior lights weren't working, the gas light came on (although I had atleast a half tank) tcs light and also the emergency brake light were on in the instrument panel. After parking the Mustang in the garage for a couple weeks until I had time to check the status of the car. I noticed the floor of the cab (passenger side) was damp. The car battery was dead (less than a year old, red top optima) and there was mold actually growing in parts of the interior of the car. I did some research regarding this issue and found it common from a failed plug under the windshield wipers next to the a/c filter. Causing the water to fill up between the firewall and the engine compartment, and ultimately leaking inside the cab onto the sjb (Smart junction box) located directly behind the firewall on the passenger side. I am very concerned for this safety issue for it can cause a serious accident if electronics fail while driving and also the fact that there is mold growing in my car from this issue. This is a common problem and needs addressed immediately.
2005 Mustang v6, right rear brake light and turn signal bulb keeps burning out. If second bulb fails on this side there is no turn signal. Have seen this defect on other 05 + Mustangs.