The warning lights on a 1999 Passat mean different things depending on the particular light. Some of the common ones include hand brake light, check engine, oil light and so many more.
Are you sure that the dimmer switch is working?
Brake lights could stay on in a 1999 Dodge Stratus because of a short in the wiring. If the headlamps are off and the brake lights are still on, check the wiring for the brake lights that is inside the trunk. Sometimes cargo in the trunk can interfere with the lights.
Brake light switch out of adjustment or defective
The warning light symbols on a 1999 VW Passat could mean the car needs an oil change or that the gas cap is not tightly on. The warning lights can also malfunction and turn on due to a bad sensor.
Brake Lights "Stuck" ONUsually that is caused by the brake light switch becoming "out of adjustment," but sometimes it can be caused by a defective brake light switch.
Could be the brake light switch or fuse.
Replace brake light switch.
replace your abs module its a common problem with v6 passat 99-2003 model.
Look for a square push button on the centre console in front of the brake lever.