Ok after looking at the manual, this might not be all that hard really. You'd use the Single Shot Falling Edge for the "Closing" circuit. Then you would use the Watchdog Retriggerable Single Shot for the "Opening" curcuit.
With the WRSS, after input voltage is applied, it looks for the trigger voltage to be applied, then it closes the contact and would provide power to the cutout for whatever time you wanted, then shut off, regardless of the trigger voltage still being present. To make it open again you would need to cycle your upfitter switch to reset the trigger voltage
To close it, using the SSFE it's the opposite, it will not close until it senses an absence of trigger voltage, then it will close the contact and apply voltage to the cutout to close it on a time delay. This one works exactly opposite of the one for the "opening" circuit. So it will not try to close again unless you apply trigger voltage and then remove it.
So it looks to me like this could actually be fairly simple. The easy way would be to wire a constant 12v source into your two relays, then hook the wire from your upfitter to the control pins of your relays in paralell.
So you'd end up with it operating something like this:
Upfitter ON:
- Both relays recieve trigger voltage.
-Watchdog engages timed circuit then turns off after timer despite still having the trigger voltage present
-Cutout opens on time delay (probably 2-3sec)
-Single Shot relay also recieves trigger voltage but does nothing
Upfitter OFF:
-Both relays lose trigger voltage
-Watchdog stays off
-Single Shot relay senses loss of trigger voltage and engages timed circuit
-Cutout closes on the time delay (2-3sec again)
-Single shot turns off after time delay ends.
Input voltage would be constant through both of these, but it wouldn't drain your battery since it's just waiting to be used. If you wanted to go a step farther it wouldn't be hard at all to just take a normal relay and hook it up so you only have input voltage when the truck is running. I'm not going to go into that though.
I may look at building one of these up, it's just going to depend on how much the components are.
Let me know what you think bird!