Amigos, servos weird or what, any ideas?

Ok, a bit of a poser, for about a month now i have had an intermittent 3 amigos,starting the car normally without touching the brake pedal. they may or may not go off after driving off, but 9 times out of ten within a mile they come back on whether i use the brakes or not, and stay on till the next morning when it all repeats itself, i also noticed that the brakes themselves wernt quite the same as they were, mainly that its nigh on impossible to stop on a sixpence, they work, and stop , but if you jump on them they dont attempt to skid, nor does the abs kick in. now for the last 3 days, before starting the car i have pumped the pedal, and held it down when starting the car, the pedal doesnt drop like i expected it to (as in servo not kicking in), also, you can feel and hear the abs doing that vibrating thing through the pedal..only for a second, and the 3 amigos flash on and immediatly go off, and then they dont come on again, ive done this every time i start the car, even if its just been off for a couple of minutes, and the amigo problem doesnt happen,tho jumping on the brakes they still wont lock or cause the abs to take over, i have got new pads and discs on and didnt make any diferance.
so.... anyone got any idea where the problem might be?
the car is a 99 xedi
cheers Dave

problem found, put the car on my mates snap on diagnostic and it said no battery power to abs, after a bit of thinking and knowing my brake light switch is only a 2 wire on or off, and the lights worked, i ruled that out, then i had a thought, a year back i had the common prob of ignition not always comming on, caused by the switch terminals under the steering column, i checked out the wiring dia and realised the abs feed also goes thro this in a roundabout way, i took out the switch gave it a good clean with emmory paper, sprayed it with contact cleaner and woopee problem solved no more amber lights