RV leveling jacks not working: Auto level, landing gear, and stabilisers

Three different systems get called jacks, and they do three different jobs. Knowing which one is not working decides which half of the work you need.

A leveling jack lifts, a stabiliser only steadies

A leveling jack takes weight: it lifts the coach off its suspension far enough to bring it level. A stabiliser touches the ground to stop the coach rocking once it is there, and it is not built to lift anything. Lippert's manual draws the line where it matters: "Once the stabilizer legs have been extended, do not use the tongue jack on a travel trailer or the landing gear on a 5th Wheel. Damage to the stabilizer legs can occur when lifting or leveling the trailer after the stabilizer legs have been extended. Doing so will void the warranty of the stabilizers".

There is a second tell, and it is in the hardware rather than the manual: a stabiliser has circuit protection that trips rather than lifting. The same document says the protection is included "to prevent the stabilizer from lifting", and that if it trips, the legs should not be extended any further. So a stabiliser that stops and refuses to go further is doing its job, not failing.

Landing gear is the front pair, and it does the lifting on a fifth wheel

On a fifth wheel, the front landing gear carries the pin weight, and it is what you use to raise and lower the front of the coach when hitching and unhitching. Lippert's unhitching instruction has the sequence in it, and both halves matter: park on a level surface and chock the tyres, then extend the inner legs of both landing gear to within 4 to 5 inches of the ground by pulling on the leg and pinning it. Doing that before you take the weight lets the gear travel less on the motor, and it is the step people skip before complaining that the front jacks are slow.

The battery, and the number the controller wants

A leveling system is one of the largest 12-volt loads on the coach, and the makers put a voltage floor under it. Lippert's own instruction for the Ground Control 3.0 is specific: "Ground Control 3.0 requires a minimum of 12.75V DC from the battery for proper operation". For its other leveling systems the same manual asks for something else again: the battery should be "fully charged and test at 12+V DC under load".

Both of those are load figures, which is the part a simple voltage check misses. A rested battery that reads 12.8 volts can sag below the floor the moment the pump or the motors start, and the symptom is a system that begins to move and stops, or one that clicks and gives up. The maker's own wording asks for the battery to be fully charged and load tested before operation, and on a coach that has been sitting, charging it first is the cheapest of the three checks. The 12-volt guide covers measuring that properly.

Ground it will accept, and the legs it expects

The maker's pre-operation list is short: park on solid, level ground, and make sure the jack locations are clear of obstructions and debris. A system that has to travel a long way to find level is slow, and one that is asked to work on a slope will refuse or fault. Keep people, pets and property clear while it runs.

On landing gear there is one mechanical prerequisite that stops people cold: the inner legs have to be down. If the outer tube is touching the ground and the pinned inner leg was never dropped, the gear has no travel left.

A fault has to be cleared before it will do anything

These systems latch their faults. Once the controller has recorded one, it will not run a sequence until the fault is cleared, and the display is where it tells you which one it is. The codes belong to your controller and its revision, so a table assembled from somebody else's revision will point at the wrong thing. Read the code off your own pad, then look it up in your own controller's documentation, which is in the manuals section under towing and running gear.

Twist prevention, which locks the rear jacks on purpose

One symptom looks like a fault and is not. If a rear jack will not operate on its own button but works perfectly when Auto Level runs, the system has deliberately locked it out. Lippert's note: "If the rear jacks will not operate individually using the method described above, but they operate properly when Auto Level is performed, the Twist Prevention Protection system has locked out the operation to prevent damage to the frame of the trailer". It is protecting the frame from being twisted by one corner, and the answer is to let the automatic sequence do the work.

What the system thinks level is

A leveling controller does not measure the world; it measures against a reference stored in it. Lippert calls that the zero point, and describes it as "the point that the trailer will return to each time the Auto Level feature is used", adding that it "must be programmed prior to using the Auto Level feature to ensure the proper operation of the system".

That gives the two ways this goes wrong. A coach that levels but sits visibly out of level has a zero point that was set while the coach was not actually level, and a coach that has just had work done on its suspension or its jacks is a candidate for the same thing. Neither is a mechanical fault, and no amount of checking the jacks will fix either.

Setting the zero point

The procedure is a short button sequence on the touch pad: level the coach manually with a spirit level placed in the middle of the floor, side to side and front to back, then put the pad into its calibration mode and confirm the point. The sequence itself differs between controllers and revisions: one revision of the automatic controller uses ten presses of the front button then ten of the rear and then Enter, while the OneControl touch panel and app have their own route through the menu. Follow the one for your own pad rather than the one that happens to be first in a search result.

Worth knowing before you start: the coach has to be genuinely level by a level, not by eye, because that position is what every future Auto Level is measured against.

The manual override, per system

Every one of these systems has a manual override, and they are not the same procedure. An electric jack normally has a drive point on the motor or a coupler at the end of the leg; a hydraulic system has a pump-side override instead, which is the same shape as the slide-out override and uses a drill on a valve-opened coupler. Because the drive point, the tool and the direction all differ per system, the sequence to follow is the one in your own system's manual rather than a generic one.

The stabiliser overrides are short enough to state, and they carry a caution worth knowing: one of Lippert's stabiliser systems is overridden with a crank handle on the end of the leg opposite the motor, after disconnecting one of the motor's wire leads so the motor cannot be backfed, and its other system takes a 5/16 inch socket on a ratchet. On that second one the manual adds: "Do not use a power tool to perform any of the override procedures since this may damage the motor".

The electric jack overrides, in the maker's own tools

Where the jack is electric, the manual gives the override in full, and it is worth having to hand before you need it. Unplug the power harness to the motor first, which is the maker's own recommendation before any override.

• A front jack takes a 3/8 inch drive ratchet with an extension and no socket, into the port on the top of the jack motor under its rubber plug. The same jack also has a manual override nut that a 3/4 inch socket wrench fits.
• A rear jack takes the same 3/8 inch ratchet and extension from the port on the top of its motor, or a 5/16 inch socket from the port on the bottom.

And here is the detail worth remembering, because it is the opposite of the stabiliser rule: for the jacks, a 12 to 18 volt cordless or pneumatic screw gun is acceptable, and the manual only rules out an impact screw gun. For the stabilisers, no power tool at all. Two overrides on the same coach, two different answers, which is why the tool comes from your own system's manual rather than from a general rule.

If it is hydraulic, check the fluid

A hydraulic system that will not move is worth checking at the reservoir before anything else, and the maker gives both the figure and the trap. Each month, check that the fluid level is within 1/4 inch of the fill spout lip while the jacks and slide-outs are fully retracted. The note attached to it is the one people get wrong: "always fill the reservoir with the jacks and slide-outs in the fully retracted position", because filling it while they are extended means it overflows into its own compartment when they retract. The manual's own advice for a jack time-out fault is the same list: check for obstructions, leaks, fluid level, and voltage to the power unit motor under load.

What to do about the legs before you drive

The maker's instruction is blunt and it applies to every system here: make sure the stabiliser legs are fully retracted before moving the trailer, and the same is true of leveling jacks. A coach that will not retract is not a coach you drive. If the legs will not come up and the trip cannot wait, the honest sequence is: clear the fault and try again with a charged battery, use the manual override to retract each leg, and if that fails, get the legs up by whatever means your system's manual describes before the wheels turn. Driving with a leg down damages the leg, the mount and often the frame.

The most important line on the subject is not ours, and it is worth its own paragraph rather than a bullet in a list. Lippert's manual carries it for every leveling system it builds, in almost the same words each time: "The Lippert leveling system is designed as a "leveling" system only and should not be used to provide service for any reason under the trailer such as changing tires or servicing the leveling system". It then states the consequence plainly: "Any attempts to change tires or perform other service while trailer is supported by the Ground Control 3.0 leveling system could result in damage to the 5th wheel and/or cause death or serious injury". One of its earlier systems adds the practical version of the same advice, recommending a trained professional be employed to change a tyre on the unit.

A jack that holds a coach level is not a jack stand. The three other prohibitions are the same family: do not lift or level on extended stabilisers, do not put a power tool on a stabiliser override, and do not move the coach with a leg down.

Cost here is decided by which of the three systems has failed and how accessible it is, not by the size of the parts, and the range starts at nothing.

At the bottom are the faults that cost only time: a battery that needed charging, a coach parked where the system would not accept it, a fault that needed clearing, a zero point that needed setting. Those are the cheapest outcomes, and they are why the checks come before the parts.

In the middle sit the parts that bolt on: a jack leg, a foot pad, a sensor, a switch, a controller. A jack is a component rather than a system, so the labour is mostly access, and access on a leveling system is generally better than on anything else under a coach.

At the top is anything hydraulic, where the pump, the manifold and the rams put the job beyond most driveways, and anything that has been damaged by moving the coach with a leg down, where the leg mount or the frame is now part of the repair. That last one is the expensive shape of this fault and it is entirely preventable.

Every fault on these systems is a 12-volt fault until it is proved otherwise, and the 12-volt diagnostic guide is where the voltage checks are. The other mechanism with a published override is the slide-out, and the makers' own leveling documents are in the manuals section under towing and running gear.