2023 Discovery 38K. All three slides were in and wouldn't budge, didn't hear any noise like they are even trying to move. Tried the retract to see if they might at least bump a little, nothing.
After a lot of online research and speaking to three non-Fleetwood techs, and one Fleetwood tech, and some trial and error here was our solution.
Our slide-out ignition relay was bad. Our Parking Brake Light was also on, even though the brake was set.
One person showed a photo of their fuses they keep on hand. That is unfortunately not the style Fleetwood put in our 2023 Discovery. I turned off all breakers, unplugged from shore power, removed the negative cables from the Chassis and House batteries, then removed the circuit board (not easy) and then removed both relays by heating up the contacts. These are not the typical blade connectors that plug in. Every stupid thing on this circuit board is soldered. The board is ~$1,700 from Rev RV. There was another company that used to make these for Fleetwood but now it is Rev RV parts only.
DigiKey from Thief River Falls, MN was awesome. I ordered four relays (used 2 and have 2 spares) for about $4 each and they overnighted them for $29 and they actually got here overnight. My electronics friend said he orders a lot from them. Soldered both relays on the board. They are identical and figured as much trouble as this has been, I'm replacing both.
Success!!
The Fleetwood tech said to check fuses 6, 7 and 8 in the Battery Control Center. Fuse 7 was bad as well. Got the Super Slide out but the kitchen and bedroom slides pop the fuse. He said to check the slide out ignition relay in the same area, then may be a pinched wire somewhere.