2003 GMC Sierra, 5.3, 4Wd, auto, runs excellent. Completely at random, sometimes 2 or3 times a day other times not for a month or 2, all the warning lights on the dash will come on, the clock resets, and there is complete loss of power all for 2 or 3 seconds and then the warnings lights go off, power is restored until the next time. I never have to restart it so I'm thinking the motor never completely stops spinning. Replaced the computer, ignition switch twice, alternator, battery, CPS, and ignition relay. Still does it no idea why! All suggestions will be helpful! Thanks

 

Come on now you gear heads, ( me included), what's the solution to this problem? I can't be the only one in the history of Sierras to have experenced this problem! need some help here! And also I forgot to mention that no codes are being set. thanks

 

Ok so the problem turned out to the Body Control Module (BCM)

 

yayyy!

If not that I was going to say pull out the fuse box under the hood, check and/or replace.