2000 sable abs/brake/traction control warning lights

Hello All, new here, in need of help.
my 2000 sable has a problem with the warning lights, abs/brake and T.C.
the lights come on at different times no matter what the car is doing, they stay on a while then go out in this way. 1st the T.C. light flashes once then a moment latter the warning lights go out. Then sooner or later they will come on again. Tryed to pull codes, none avialiable, talked to the Merc. service dept. they said poss. the wiring harness for the abs located drivers side f. fender.
Any Ideas ???
Thanks
Mike

I've checked all the wheel speed sensors and all the wiring I can find, cleaned the sensors, all checks ok, I'm still having the same problem.
Any thoughts ? any help would be great.
Mike