2002 chevy silverado

Im having a terrible issue with my instrument cluster and every replacement has the same problem. Gauges and odometer and lights issue. Just bought it recently, the truck. Took out the aftermarket stereo and once i took it off and wired up my new one which was much bigger then it wouldn’t turn on. Suddenly my cluster is having problems. Constant 12v in radio harness only has .2v. I took a 12v and spliced it to the radio constant and suddenly my gauges are moving and working again until I take the 12v power away from the radio constant. Just wanna know what to begin with diagnosing and how they may be connected in some way because I am totally lost.

Edit:

Just figured out ever since I ran that 12V to my radio, the running light on one taillight now is getting too low voltage and won’t work

 

We need to know your vehicle details to help you, so please post them.
For electrical issues the first step is always to check your fuses.

 

Sorry about that it’s a 2002 chevy silverado

Just figured out ever since I ran that 12V to my radio, the running light on one taillight now is getting too low voltage and won’t work

 

sounds like you wired in to a bus communication wire. review your wiring connections.

 

Where would I begin to check?

 

you need a wiring diagram for the radio for your radio option build. an install shop may have one or bulldog security used to have them on the internet.
once you have the diagram, make sure you connected to the right wires.

did you buy a connector or hardwire everything?

 

Free Car Alarm, Remote Start, and Car Stereo Wiring (the12volt.com)

 

I used crimp connectors and I connected color to color but I can check and make sure that the colors meant the same thing but all the functions worked right. I wonder why it worked up until I cut the wires from the adapter that went to the radio in it. When I removed that my cluster went dead but my two gauges that didn’t work previously began working. I just don’t know why it only began when i just cut the wires

 

what colour wires on the vehicle harness did you cut

 

I didn’t cut anything in the vehicle harness, I had a radio connected with the adapter harness and I cut off of that, then spliced in the new wires. I noticed as soon as I put my new radio in that it wouldn’t come on and my cluster was dead. I tested the yellow wire in the radio harness and it was only getting .2v from the factory connector so I had ran a wire from the red constant 12v wire that goes up your steering column in the ignition harness and i jumped that to the yellow wire on the radio harness. Hopefully this helps