Don't drive it anymore until the brake boost problem is fixed. As said above, it is probably going to be either a leak to the booster or the booster itself.

As far as the brake pad wear light, check the pads to see if they are above min thickess (2 mm). If not, replace them. If they are thick enough, check to see of the sensor is properly connected and there are no cuts in the sensor or wiring to the sensor.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record