The rear slide on our '04 36' Monterey has started to act up.  This slide is driven by an electric motor (not hydraulic).  We have found that the house batteries have to be at peak charge to operate the mechanism.  We have found that if the system fails we can either connect to power or start the generator and all is fine.
The system is basic but I am not sure how to trouble shoot.  We have the electric motor, a brake on the motor, and a heavy duty 6 lead rocker switch.  All connections at the motor and switch are tight and clean and I have 18 month old Interstate house batteries which I removed, cleaned, tested, and reinstalled.
This is a new problem and has not given us trouble in the past.
Any ideas?

The most likely problem with your slide, from your description is an out of adjustment brake. It can also be a motor on it's last leg or a binding in the slide mechanism so the motor requires max voltage (12.7 to 13.6) to operate.  

Gerald

Be sure you do not have a dirty or loose  connection somewhere including the switch then check to amperage draw of the motor.

The only issue I have had with my bedroom slide is right after I leaned a ladder against it and basically pushed it in a bit. The fuse blew when I tried to retract it. I replaced it and all was well. I wonder if Gerald's suggestion of slide adjustment would apply here?

Jack, I have an 03 Monterey that has displayed similar behavior over the years. Usually between 12 and 18 months the room will not move when the switch is activated. Each time I remove the switch and clean the blades with a small file or sandpaper. After that it works fine. I don't remember if it was only on battery power but will know to check with external power if it happens again. Being that it works ok with shore power I would think the brake is working normally. The symptoms indicate a bad connection or ground and can be very difficult to isolate. Does temperature change affect it? You may start with cleaning the house battery ground to the chassis.

Jack said he checked the connections including the batteries.  I'd go with Gerald's suggestion re. the brake, and refer back to the thread in this forum started Sept. 13, 2009 by John Fearnow, entitled "Bedroom Slide", http://forum.bacrallies.com/m-1252886858/s-0/highlight-bedroom+slide/#num0.  

The symptoms, though, as Gerald pointed out, sound very much to me like a binding slide that requires absolute maximum voltage to overcome the bind.  A loose fastener or something causing slightly out of whack alignment could cause the slide to rub somewhere.  I know our bed slide when new rubbed very slightly on the carpet that lines the wardrobe platform next to it, so I had Bend's techs do a micro millimeter repositioning to avoid future problems.  That slide always seems to labor more than the others, so it is no surprise to me that even the slightest impedance might require maximum voltage to push the slide to cycle completion, or to just get it started from dead stop, the point requiring the most momentary power.  Check around or under the bed platform or "end tables" for any area rubbing where it shouldn't, or the entire slide off more to one side than the other.