Noisy,
If they are true "Docking lights", and you have a switch for them, about 99.99% of the time, you can turn the switch "On" but, they won't go actually on until the rig is in reverse. Now, there may be some out there that are wired different than what I just described but, that's the normal operation for them. You can check to see if it works the way I described but, it may take two people. The reason, if you start the engine, put the rig in reverse and, set the brakes to hold it while you check the docking lights, the parking brake may shut them down, not sure. So, a simple answer here is, have TWO people, one inside with the engine running and in reverse, the other outside checking the lights. Worth a try here. Do report back to see if it works this way will you?
Scott
Scott and Karla SDFD RETIRED2004 Itasca Horizon, 36GD Slate Blue 330 CAT
2011 GMC Sierra 1500 Ext Cab 4x4 Toad
2008 Caliente Red LVL II GL 1800 Goldwing KI60ND