One problem related to brake light on has been reported for the 2004 Volkswagen Jetta. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Volkswagen Jetta based on all problems reported for the 2004 Jetta.
I purchased my car back in October 2013. When I purchased my car, the mechanic said that he replaced the abs system. The lights were not on when I bought it. A few months later, out of the blue in about April 2014, I was turning my car on and the engine light, the abs light and the brake light all came on momentarily after turning my engine on as I was still in park. My car had close to 100,000 miles on it. The problem went away and shortly came back a week later. Ever since, it has been on. Every once in a while, all of the lights would go off. Luckily the lights all went off for a few days around my inspection time for the 2014 year and my car passed. Not even three days later they all came back on. This time October 2015 inspection is coming up and my lights are all on. Since the engine light is on, I cannot pass inspection. The code reader says it is a miscommunication error, or a u0121 error. I have done a lot of investigation and cleaning up the module and the contacts, cleared the codes, and my problem is still there.