Welcome to iRV2. I do not know your specific coach. My assumption is the slides are operated by electric motors. There are some items to check:
1. Find the 12 VDC fuse panel. There should be a fuse(s) marked "slide".
2. There is a control "brain" that the slide power runs through. If the fuse in #1 is okay, find the control board for the rear slide and swap it (if possible) with the one for the front slides. If the slides work, then you'll know the control board needs to be replaced.
3. Make sure any safety interlocks are not engaged. Follow the manufacturers instructions as to the position of the ignition key, parking brake, tranny selector position, release of slide locks, engine on or off, etc.
4. Check the battery power. I know you mentioned the read slide works. However, low battery power can make for interesting failures.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
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