Wife was driving home tonight on icy roads, hit brakes and the BAS/ASR Light came on and stayed on.

Specifics:
98 E300
No battery issue
No OBDII Codes
Never had problem before and no other recent problems/changes.
Would not reset with the turning the steering wheel side to side.

I read a suggestion that it is likely a brake light switch, $12. Any thoughts?

__________________
03 SLK320
98 E300TD 320k Miles
75 914
02 Suburban