Cadillac Repair: Break lights stay on periodically, break line, cadillac escalade

Question
Hi,

I have a 2002 Cadillac escalade.  Stability service light came on so I had it serviced in April.  They flushed the break line and replaced a MPA switch.  Then they said I needed to replace the power module valve for my anti lock breaks.  I decided to wait on that because of the cost.  In the meantime periodically when I shut off my truck the three break lights stay on and drain my battery.  So, I just had my power module valve replaced last week thinking this would solve the problem.  Well, to my luck my break lights came on again yesterday when I turned off the ignition.  I brought it to the shop and they did diagnostic and no codes are popping up.  After 1800 dollars I am completely drained from this problem.  Could it be something they did in April?  Or something totally different?

Thanks,
Amber Simonitch

Answer
Perform this test procedure which will require 2 people.

1. Have one person stand behind the vehicle and watch the brake lights.

2. You reach down and using your hand lift UP the brake pedal towards you and see if the brake lights go out.

Let me know.