Colorado Electrical Troubles

I have a 2006 Silverado that rear lamps have recently quit working. A turn lamp and backup lamp on opposing sides.

One was from loose socket contacts and the other was oxidation of lamp contacts. You can bend socket contacts closer to make them tighter and clean bulb contacts. It's been several weeks now and all is fine.

On most vehicles there are 3 blinker bulbs on each side. One at the front corner, one at the rear corner and a third side repeater usually mounted in the front wing, (fender).
Some more modern car companies have started fitting the side repeater into the door mounted 'wing' mirror body.
The blink rate will usually be around 60 to 120 flashes per minute. If the rate on yours is usually slower, a higher speed flash suggests there is a blown or missing bulb.

Could be a faulty ground at one of the rear lamps or possibly a wrong bulb has been fitted.

Certainly it seems the rear lamps will be a good place to begin the diagnostic process.

Sounds like its a bad bulb or the grounding on it. I had the same problem on my 06 Colorado. I bought new bulbs put on in and it still didn't work turned around and put other one in and it worked. So I'd try that first

Not sure I follow your story.
The front and rear turn signal should blink on one side. If the tail lamps are not working, it could be a fuse or a problem with the wiring. And the tail lamps are on the same circuit as the front parking lamps.

netural wire broke or bad connection or two blown bulbs.adrian,,,,,

Usually when the turnsignal blinks rapid this is a indicator that the turn signal bulbs is blown, you will need to check both the front and rear signal to see which is not working, and then change the blown bulb or bulbs.

if you replaced the bulb and it still dont work turn the car on and off 3times,,the cars computer stops giving the wire power when it sees the bulb is bad so after you replace the bulb it still will not work till you cycle the key a bunch of times or clear the codes,if you got a scanner, if that still dont work,then the headlamp harness is shorted out,thats common too

Probably a broken ground wire. Check it with a test light. Make sure you have a good ground, and then stick the test light right in the socket to see if there is power. If there is power to the test light, but still none to the bulb, it's a ground wire. If there is no power, its a power wire. Just keep poking the wires, and work your way back until you find some power. Make sure you have the lights on when you're checking. Good luck.

replace the drivers front bulb. There are 2 different elements in the bulb 1 for park lights 1 for directional