One problem related to brake sensor has been reported for the 2004 GMC Sierra 1500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 GMC Sierra 1500 based on all problems reported for the 2004 Sierra 1500.
GMC & chev k1500 series pickup trucks 4x4 front wheel bearings abs brake censor unit I had 2 sets of these go bad on qa pickup with less than 35000 miles on it these wheel bearings are not bad they just become a little lose but are still in factory spec. There is a abs sensor in between them and the unit will malfunction in this condition which will not let you stop when on dry roads I ran through 2 stop signs trying to stop with 2 feet on the brake pedal this condition is not just with my truck I have over 12 friends that have the same truck 2002 thur 2006 and we have all had this happen to us if you want names and #'s I can get them.