Pulling out the storage bins, more rust (sigh) anyway, I found a clarion box, must be amp for rear speakers? There was another metal box next to it (driver side) with a circuit board inside and a large connector.
What is this, anyone?

 

drivers side gold box = cruise control
the Clarion things are door stops,. OPPPS i mean amps

 

The amp on the driver's side is the rear amp, the one on the passenger side is the front amp.

Bin rust caused the passenger side to be inches deep in water which destroyed some of the wiring Fixing the wiring didn't help so the amp must be fried too...