My wife and I just bought a (REPOed) 2009 Bighorn 3670RL. I am have no manuals yet. There is only one switch which runs all the slides. Is there a way to select which slide you want to run?
As Jim mentioned, in the hydraulic compartment there should be a manifold on the pump with 4 knobs, one for each slide, and there should be a label under the pump tray indicating which slide they control. There is also another switch next to the pump that will operate the slides, just like the one in the cabinet inside the coach.
Make sure you have the manual crank rods to operate the front jacks and electric rear stabilizers, should the motors fail. Test the rod (if you have it) for the rear stabilizers to make sure it fits. Mine had to be modified some. Make sure the rod to lower the spare tire is on board. If the hydraulic pump fails, you can still operate the slides via the 1/4" hex fitting on the end of the pump motor, using an electric drill/driver. Best to buy the bit and an extension to reach it and keep it in your tool kit. There is a hole in the basement wall for accessing it. If you look in there, you will see a sticker that covers the end of the motor. Peel it and insert the drive in there.
You can download a pile of manuals on the hydraulics, axles, etc., from the Lippert site:
www.lci1.com