[joedoh]

one of the things I see the most common when guys install radios to GM vehicles, is they get the red and the yellow mixed up. in the aftermarket radio harness which should use SAE standard wire colors, red is ignition and yellow is 12v+. but in GM, especially ones with aftermarket harnesses, yellow is ignition and red or orange is 12v constant.

so you can see what happens, people hook red to red and yellow to yellow. since the radio needs both the ign and the 12V hot to turn on, it works, and when you turn the key off it turns off, but since there is no 12v on the 12v constant wire, the memory gets cleared. I used to be a stereo installer a million years ago and I fixed this 2-3 times a week.

so check. in a standard radio harness, red should be switched ign, yellow should be 12v constant. use a multimeter and find out if you have them switched.