The sensor wire is a ground for the light. As the pad wears the rotor grinds off the plastic cover on the sensor and makes contact with the rotor, which is a ground. Being new pads, I would suspect a wire harness problem. If the harness has a exposed area due to age, it could be grounding out at times. I actually have this problem when the steering wheel is at the full left turn position.
If it occures with a particular wheel postion it could be the harness. Sealing the open wire could cure this. Finding the open wire would be the work.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car