I guess all unit's interlocks are different. My 2010 Allegro has to have the engine running and parking brake engaged for them to etxtend. I even found out that if I shut the engine off during the retract, they stop retracting! When it's cold out, it takes a real long time for them to get up to "travel mode". I have to let the rig sit idling till they get all the way up. Almost went down the road with the jacks partially extended. It's the same for my slides. I have to crank up the engine to run the slides in or out.
I hope the OP got his fixed!