I just installed an aftermarket stereo in my 05 Sierra, and now my speedometer and odometer won't work. The only wires I used were wires that were previously plugged into the stock radio.

Any ideas?

Thanks.

unplug the radio and see if they some back. tough to imagine what on would have to do with the other though, the pcm controls the cluster via the data bus. you didnt do anything to the data wire did you? normally purple.

I figured it out.

I used (unknowingly) the 12v wire from the speed sensor to power the radio. Turns out that all I had to do was cut and cap that wire and all is now well.

Whew!