Big D 1971

So I replaced the carpet in my 2008 Chevy Silverado crew cab 4x4 LTZ with a 5.3L V8 with active fuel management. I removed the two front driver seats, the rear seats, and console between the two front seats.
When I reinstalled everything, I plugged in the large connectors under each of the seats, the large connector under the tray in the center console, as well as the small one close to it. Then attached the two plugs for the radio control for the rear seating, and the two 12v outlets, the one in the console box, and the one under the radio control. I have not reinstalled the rear seats yet, and now the truck will not start. The dash lights come on, the radio doesn’t work, the windows don’t work, the seat controls do work. Getting a P1516 error code on the check engine light. I also did not disconnect the battery when doing all this. Any ideas what could be causing these things to happen? Literally no problems before I removed the seats, etc. In hope it has not become a boat anchor...I even had a Chevy dealership mechanic (not at the dealership) to look at it and he was stumped.

Gumby22

What’s probably happened is the battery is discharged enough that it’s unable to deliver adequate starting current.

Besides the dome lights being on due to the open doors, there are control modules for the seats and radio that were disconnected in this process. These things cause the communication network to remain active for an extended period of time which can drain the battery relatively quickly.

There’s also the risk that one of the modules is malfunctioning due to being unplugged without disconnecting the battery - GM has issued a recurring TSB regarding this since about 2000. Although none of the modules you disconnected directly affect the starting system, they are connected to the BCM via the serial data circuit, and could be causing the BCM to malfunction as well.

It’s unlikely any permanent damage has been done, but to resolve any malfunctioning that could be causing the no start, your best bet is to perform a hard reset. Disconnect both battery cables (negative first) and use a clamp or jumper wire to connect them together for at least an hour (overnight if possible). Make sure to isolate them to prevent accidental battery contact during this time.

What this does is clear the active memory (no security/anti-theft protocols will be cleared) of the modules and revert them back to their default state which can resolve program glitching/malfunctioning.

While the reset is being done, charge the battery.

If this doesn’t resolve the issue, and no helpful codes are stored in the PCM, the next step is to have the entire system scanned to identify possible communication problems (requires professional or dealership scan tool).