[colonel6632]

guys. i have this same problem. heres what i worked out

it seems if you have 2 wheel bearings out, cruise control will stop working. my front to hub sensor wires were broken. fixed one, cruise works again. so if your abs, brake and service vehicle soon lights are on, look at that.

if no dash lights are on.
does your cruise work in the day time? without the headlights on? mine never fails then.

at night time, with the low beams on, the cruise works, but if i turn on highbeams on, more often than not, the cruise cuts out. if i tap the brakes really quick, the cruise will come back on.

my light setup, 6000k hid lights in lowbeam, 5000k lights in highbeam, all 4 lights come on when the lights are on high.

my theory is that there is too much current being drained on the stock wiring when the high beams first kick in. it has happened when the headlights turned on once it became dark enough outside.

now on your driver fender under the hood, beside the intake box, there is a little black box screwed to it. now mine broke off, and that did all sorts of crazy things to my eletrical. so i cleaned off a nice new spot and put a self tapping screw in for it. that helped alot, but still happens.

check to make sure your cruise control module has good connectons (little box beside the motor, in the ecotec atleast).

i'm going to install 2 relays that power the hid ballasts directly from the battery, and see if that helps

i know thats alot of reading, but hopefully that helps out. if you have any questions i'll be following this thread for a while