Chevrolet Repair: Check engine light is on, chevy trail blazer, 2006 chevy trail blazer

Question
Bought a 2006 chevy trail blazer at an auction, Check engine light is on and we hooked up three deferent code readers and they want pick up or read anything, they work great on other vehicles, it runs great, drove it home running about 80 most of the time and its a 4 hour trip, what might the problem be ? only problem we had was and still is, the low beam lights or running lights want come on, had to drive at night with high beam lever flipped forward, have a headlight switch on order.

Answer
GOOD MORNING WILLIAM, CK ALL OF YOUR FUSES FOR THE CK ENG LIGHT PROBLEM. SOMETIMES A FUSE WILL BLOW AND NOT LET THE PCM READ ANY CODES. IF ALL OF YOUR FUSES ARE GOOD YOU MAY HAVE A PROBLEM WITH THE PCM..MAY NEED TO TAKE THIS TO A SHOP THAT HAS GM SOFTWARE  [NOT GENERIC] CK THIS AND GET BACK TO ME..AS FAR AS YOUR LIGHTS GO,I WOULD BE VERY SURPRISED IF THE HEADLIGHT SWITCH IS YOUR PROBLEM. HAVE YOU ALSO CHECKED YOUR FUSES AND RELAYS UNDER THE HOOD..THERE IS A RELAY THAT CONTROLS THE LOW BEAMS AND DTR LIGHTS. THERE IS ALSO A HEADLIGHT CONTROL BOARD MINI MODULE..YOU MAY WANT TO CK WITH YOUR DEALER ON WHERE & WHAT CONTROLS THE LIGHTS AS WELL. ALSO  IF IAM THINKING OF THE CORRECT CAR THERE IS A SET OF RELAYS AND SOME FUSES UNDER THE REAR SEAT AS WELL. CK YOUR OWNERS MANUAL TO BE SURE,OR JUST LIFT UP THE PASS SIDE REAR SEAT [BEHIND THE DRIVERS SEAT]AND CK ALL OF THESE FUSES AND RELAYS.CK THE ABOVE FIRST BEFORE GETTING INFO FROM YOUR CHEVY DEALER. YOU CAN CALL THE PARTS DEPARTMENT AND THEY HAVE ALL OF THIS INFO FOR YOU IF NEEDED..GET BACK TO ME ON HOW YOU MAKE OUT..GOOD LUCK,,,TOM