Was driving my trailblazer the other day and the dic started going screwy. It keeps saying unknown driver, then all the dash warnings come on, abs, service lights, brake light,seat belt ect. Gauges all work at this point, but if i turn the truck off and then back on again 50 percent of the time the whole dash goes blank,nothing works......and i have to pop the fuse in and out, then the whole process repeats its self. Anyone with a idea..pulling my hair out! I have told it could possibly be a bad ignition switch or wires under the drivers seat shorting out.

 

Fixed it! Found the issue on mine. The dash lights would cut out randomly and leave nothing but the gauges working. Then it would give me unknown driver and not start, no radio and no dash. Some days we would go to start it and the battery would be dead. Ongoing issue, intermittent. Today it stayed on unknown driver long enough for me to troubleshoot so I: 1. Put key in the ignition and turned it to On 2. Removed the fuse cover under the back seat. 3. Pulled module fuses until suddenly the door ajar started sounding and the radio came on. 4. Looked up the fuse location. For me it turned out to be the PDM, which stands for the passenger door module. I have had issues with the passenger door electronics before so this didn't come as a great surprise. It seems any module that is connected to the BCM; DDM, PDM, Radio, Ect.. can cause this kind of issue so just remove power from each of the modules until you find the culprit. Best of luck.