Not pretty, but maybe an inexpensive wireless webcam and small flashlight on the end of a stick?
Since you aren't sure if they went out when you dumped, the webcam might let you see if they are still in there or not. And if they are, the webcam might help with the extraction.
Just thinking outside the (black) box....
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.