1997 W140 S500 ESP & ABS Lights
 

This is on a '97 S500. I've been chasing this problem since I bought the car in November. After driving for some period of time, could be anywhere from 30 minutes to a day or more, the ESP & ABS warning lights will come on. If the car is turned off and then restarted right away the lights will stay on, but if it sits for about hour the lights will come on when it's restarted, but will go off as soon the speed reaches about 10 mph.

I replaced the brake light switch and the lights stayed off for about a day, but then the behavior resumed.

Does anyone have a suggestion as to what I should look at next? I'd hate to start just throwing parts at it.Thanks.