Dodge: 99 1500 P/U ABS light, brakes rotors, dodge ram

Question
I have a 99 Dodge Ram pickup that I had front brakes (rotors and pads) replaced on a week and a half ago.  This past Sunday (10 days later) my ABS and parking brake lights came on.  It took me awhile to stop the truck.  The peddle went to the floor, but I stopped ok with additional pressure.  I turned the ignition off and back on.  No lights, so I ran my errand.  The light came back on, no brakes again.  By the time I got home, the brakes worked once, jolting my forward with whiplash.  I took the truck to the same mechanic.  He says it's the Master Cylinder, which he has replaced.  The brakes now work, however the lights (ABS/Parking Brake) won't turn off.  The computer doesn't indicate any problem.  I want my truck back.  He wants to find the problem.  Is it a sensor, air in the brake line, what?  I'm fed up and broke!

Answer
The only thing it could be is to make sure he bench bled the master cylinder before he installed it,what this does is primes the master cylinder before installing it on the truck.If he's installed a new master cylinder he should have done this providing he's a pretty knowledgeable mechanic.And it could very well be air in the line,they need to be bled really well after any brake work is performed.But naturally if you asked him if he bled the master cylinder he will probably say he did.But i'd ask him anyway to be sure.