As far as I can tell, the cable just sends a signal whenever the IR sensor bar on the inlet rack is activated/tripped, the print dryer turns on for I think about 20 minutes after it last receives a signal from the main unit, and the replenishment pump runs a 'cycle' about every 20-30 seconds while the bar is tripped. I'm not able to set up the machine itself at the moment to probe the connector, sorry. I don't see any way for the dryer to turn on/off without a signal from the main unit, there's no sensors for paper as far I can can tell in the W/D unit, just temperature sensors for the dryer. I just did a continuity check on the cables,
going off the pin numbers for the SD-30J here, the ground/shell on one end connects to the ground/shell on the other end, pin 1 goes to 1, 2 to 2 and 3 to 3. No crossovers or switched pins.
I've also attached the manual for the W/D unit, in case you don't have it.