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Ropetin · 05-23-2016, 06:52 PM

It's time for another one of my semi-regular "what the heck is up with my rig?!" questions. This time it is the jacks. I have a 2011 Tiffin Alegro 35QBA (gasser) with an HWH 725 (I think) jack system. The jacks came up fine when I moved the rig this morning, but when I tried to extend them, they wouldn't come down all the way. The front ones came down a bit then stopped, then I tried the back ones and they moved a bit, but not all the way down. After pulling them back in again, I tried them up and down a couple of times, never with any luck getting them all the way down, but always able to get them back up no worries. I'm not at a point where they won't come down at all.

Key things to note are;

1: the front slides, which are also hydraulic, come in and out fine.

2: When trying to bring them down I hear the pump firing up, but it doesn't sound like it is taking any load (just an interpretation)

Things I've tried;

1: Letting the engine run for a while in case the chassis battery needed a top up. Haven't tested it, but the engine starts fine so that makes me think it is OK

2: Checked the house batteries under the apparently false impression that maybe the jacks are powered off that

3: Poked at everything I can see in and around the pump area to make sure nothing is loose or looks off

As you can tell, I'm a total technical novice, so I really don't know where to go next. I found this link - http://www.irv2.com/forums/f103/hwh-...nd-101829.html - which seems to cover the same symptoms and talks about either fuses, solenoid or shuttle valve. If I hear the motor spinning when I press the buttons, that shows it isn't a fuse problem, correct? Does it also exclude the solenoid, or could that still be a problem? As far as the shuttle valve goes, that thread seems to suggest it is an easy thing to fiddle around with, but other links I've found online suggest it isn't a minor thing to meddle with. Any thoughts on shuttle valve fiddling for a novice like me?

Melmoses · 05-23-2016, 08:46 PM

Have you checked your hydraulic fluid? My slides worked fine but the PS Jack would not extend. Found that I was a quart low on fluid. Filled up to level and all jacks worked. The fluid extends the jacks while the springs retract them so hopefully that is your issue.

**Lt Dan** · 05-24-2016, 08:02 AM

I second Mel's diagnosis. Your slide hydraulics use the same amount of fluid to both extend and retract. All they do is move the fluid back and forth on either side of the ram. On the other hand, the levelers require "new" fluid to extend since they don't use fluid on the bottom of the ram to retract. Retraction is strictly by spring power. Because of this, the slide rams do not deplete the fluid supply in the reservoir but the levelers will.

HGC · 05-24-2016, 09:15 AM

We had similar problems on our 2014 36LA. Check your connections at the multiplex box in the compartment under the driver side. And check for a fuse going bad. Just found the ground from the inverter loose. This is a good time to check the tightness of all wires especially in the transfer switch. Remember to disconnect your power sources and wrap your screw drivers with electrical tap to avoid arcing from shorting contacts just to be careful. Of course check your main(chassis) battery contacts because that is where your power for the jacks comes from. It connects directly to the multiplex fuse box. If it doesn't have enough voltage the 12v system powering slides and jacks won't work. Good luck!

Ropetin · 05-24-2016, 07:32 PM

Thanks for the help everyone! Turns out it is the shuttle valve, which was mentioned in the thread I linked in my question. One is being ordered as we speak, so hopefully will only be a couple more days without jacks. The DW, two kids, and three cats are already going crazy being in a cramped, wobbly house!