3120rl problem w slides closing on 12v

[OShag]

Hey there. I had the exact problem during a trip south to Arizona earlier this year. We have a 2020 3120RL that was doing the same thing. Sucks to have to stop 3-4 times waiting for the system to reboot while just trying to put the slides out/in. The problem also happened when trying to lift the 5er off the truck using the front jacks. I also thought it was a battery so I replaced that first. Turns out it WAS the lack of an 80 amp fuse as per the hydraulic pump specs already mentioned in this chain.

Since we were travelling after the problem started, and after research on the forum, I made a stop at the local Napa auto parts and bought an overpriced 80 amp fuse, some 4 Ga battery cable - by the foot, a couple lug ends, solder and a torch. Nothing like not having any of my electrical tools with me. The self-resetting fuse is about $20 on Amazon, or $50 for the non-self-resetting one at Napa. Anyhow, soldered the ends onto the cable and went into the front bay where the battery and hydraulic pump are.

Picture 1 shows the two factory self-resetting fuses. They trip when they reach their limit (20, 30 or 40 amps, I don't remember). Because they are the first thing between the battery and EVERYTHING else in the 5th wheel, everything shuts off - including the In-Command. They reset in a second or two, and the in-command takes a while. Then you get another 5-10 seconds of hydraulic pump before another reset. The pump draws more amperage at start up, which is why the company says to put an 80 amp breaker instead of what Keystone did.

I simply:
1. Disconnected the wire to the hydraulic pump from the output side of the fuse (it's easy to see which one since the big battery cable comes in one side and the same size big cable leaves the other side to the pump;

2. Attached one end of my new cable where I took the pump one off; and

3. Attached both wires to either sides of the new 80 amp fuse and screwed it to the wall (the wall is wood so a couple course-thread screws held it on just fine.

Since we had the problem when using the front jacks too, we did the repair during our trip. Many folks have used an 80 amp self-resetting fuse (that automatically resets like the underpowered ones) but I couldn't get one at the auto parts store while travelling. So I'll have to open the door and flip it back on if it trips. But, I have made two trips since then and have had no problems at all. So I haven't purchased a new fuse - I'm living with what I did in the field since it hasn't tripped one since then.

So, the right sized fuse is what was needed. No problem. Also, short term, as long as you're hooked up to shore power it shouldn't be a problem.

Best of luck and safe travels!