I have just picked up a 2012 Express 2500, that is your basic fleet van. Crank up windows and basic AM/FM stereo. I was going to install a replacement stereo today, but am a bit confused with the wiring. I've done many stereo swaps, so I am not a rookie. The old radio has 2 connectors, the smaller has 4 wires. The larger has the power, etc. First question, what is the 4 wire connector for? Secondly, I am looking for the wiring convention of the van. Thanks

 

Great question! I am looking for the same information! I also have a 2012 Chevy Explorer conversion van on the Express 1500 135" wheel base chasis. If you get that wiring diagram, I would love to see it too! Thanks in advance for any assistance you can provide. I am looking to upgrade many aspects of my van audio system, both in front on the dash and in the back on the video entertainment system.

 

schematics are available on gmupfitter.com.
Likely the small connector is data to enable chimes and Onstar connection.

 

Does anyone sell a radio install kit for these vans? I know they exist for 02 and older. Should have a pigtail that the factory harness plugs into and you wire to the pigtail that comes with the aftermarket radio.

I didn't bother with either of mine because the wiring is pretty standard and they're both old hunks of junk and I didn't see the need to spend the extra on.

 

Yes, I installed an Android system in my parents (now mine) 2004. You need a double DIN bracket, harness adapters, a door chime module, and a radio. Maybe also an antenna cable adapter.
Finagling the cluster cover off is a bit tricky and cramming all of the wiring in behind a big radio is definitely hard.