To the OP:
1- Did the Three Amigos come on before or after you changed the brake pads?
2- What rotors and pads are you using?
3- How long ago did you do the brake job?
4- Are you getting a log of brake dust?
5- What size tires are you running, different than original?
6- Do you have a lot of aftermarket weight bolted to the truck, bumpers....?
Note- Some combinations of rotors and pads, especially aftermarket, can cause the breaks to squeak. The squeak frequency interferes with the wheel speed sensor and causes a False Code that turns on the Three Amigos. Keep in mind that the squeak does not need to be heard by you, it could be at a frequency that you can not hear but still interfere with the wheel speed sensor.
Use the ABS Amigo and clear the hard fault codes (this can not be done with a standard ODBII reader)
Also, the DII brake system does tend to feel soft but to some degree this is part of the design. It is not supposed to "lock up" as locking up and skidding is not an ideal situation.
Regards,
Brian