GM-GMC: chev 4x4 1ton 2004 truck, service brakes, best bet

Question
abs&brake light as well as service brakes comes on sometimes at start up. If i shut off and re start everything ok. brakes ok checked and also new as of 10-4-08. thinking sensor of some sort? 110.000 miles well serviced. new wheel barrings (75.000) miles

Answer
With out knowing what engine etc is in this truck, it is possible that you have a hydraulic assist unit (for diesels) or a standard vacuum assist (for gas).  I have seen the solenoids for the vacuum assist units malfunction and cause a SES light.  Unfortunately I don't have any experience with the hydraulic assist units. Inorder to know what part of the system is malfunctioning, your best bet would be to have someone read the codes for you.  Then you will atleast have a direction in which to start looking, with out that it is blind guessing.
Hope this helps.