Check the ground wire for the rear lights in back underneath where it attaches to the frame/body/bed. It may be broken, corroded or loose.
bulbs are to small Check the fuses.
No. there is no relay for the turn signals.
check for a loose ground wire
a malfunction of the hard drive to send signals to the processor
Replace the flasher relay if the lights come on but do not flash.
no, the Chevy Colorado seems to be the only GM Vehical that does not beep when you lock it. Read the owners manual, I have a 2005 that beeps when I lock it. It can be programed to beep and flash the lights, just flash the lights, or just beep.
either a bulb or the signal flasher relay located on the fuse panel usually opposite the hazard flasher relay
If the lights come on but do not flash, replace the flasher relay. If they will not come on check the fuses.
Usually this tells you that 1 or more lights are burnt out.
If the lights come on but do not flash then the turn signal flasher relay is defective.
emergency blinker
Flasher relay is bad if the lights come on but do not flash. If they lights do not come on at all then the bulbs may be blown or the fuse if blown.