RV Entry Steps Not Working: The Test That Splits the Fault

The controller is a switch that watches current. Lippert: the step shuts off at the end of an extension or retraction cycle by sensing the spike in motor current, and the same spike occurs, and the motor shuts off, if the step meets an obstruction. That is why a step stops when it hits a rock or a leg, and it is also why a step that stops part way is not necessarily broken.

It has four inputs. Lippert lists them: a door proximity switch input, a hold or cycle step input, a porch light input, and an ignition on input. The outputs are the bidirectional motor drive and a 12 volt brake release.

The door is what starts it. Each time the door opens, the door proximity input extends the step; when the door closes, the step retracts. Kwikee's installation guide adds the detail that matters for a switch that has drifted: the step assembly should begin to extend when the door is opened between one and four inches.

And the ignition overrides it. Lippert states that when the ignition is turned on and the door is closed, an extended step will retract regardless of the position of the hold and cycle switch. That is the safety interlock, and it is the reason a step that will not stay out while the engine runs is behaving correctly.

The four wires at the connector are the whole system. Kwikee's testing procedure names them: the red wire is the power supply, the brown wire is the door switch, the white wire is the step lockout switch, and the yellow wire is the ignition override. Every test below works on those four.

Kwikee's own procedure opens with the fork that saves the most time. If any of the step functions do not work, the source of the malfunction is either in the control unit or the motor, and the next step is to test the motor. If all of the step functions do work, the malfunction is either in the door switch, the step lockout switch, or the vehicle wiring.

In plain terms: if the step will not move at all when you test it directly, the problem is in the step assembly. If the step moves correctly when you test it directly but not when you open the door, the problem is in the coach wiring or the switch, and the step itself is fine.

Erratic behavior points somewhere else again. Kwikee states that if the step does not work or operates erratically, for example extending part way and shutting off, the first item to check is the vehicle battery, because low supply voltage may cause erratic operation, and poor ground connections may also cause it. A step that behaves differently every time is more often a supply problem than a mechanical one.

Testing the motor

Disconnect the two-way connector between the step motor and the control unit, connect the motor's red wire to the positive battery terminal, and touch the motor's yellow wire to the negative terminal to extend the step. Kwikee's verdict: if the step extends and retracts during this test, the condition of the step motor is good.

Two things about that test are easy to get wrong. The maker warns not to leave the wires connected once the step has cycled either way, because failing to remove them will burn out the motor and void the warranty. And on steps fitted with a reverse polarity plug, the red and yellow connections are reversed to perform the test.

Testing the controller

A controller that will not shut off is the fault behind a step that runs continuously. Kwikee's test removes the four-way connector and the two-way connector, puts a voltmeter between the red and yellow motor wires on the control unit side, and reconnects the four-way. If any voltage registers for more than five seconds, the control unit is not shutting off and may be defective. The maker adds a warning worth following: disconnect the four-way connector to keep the step motor from overheating.

Testing the door switch

With a voltmeter between the red wire and the brown wire at the four-way connector, the reading should be a minimum of 12 volts DC when the door is closed and zero volts when it is open. If the readings are incorrect, the switch is the problem. Kwikee also publishes the lockout switch test, which reads a minimum of 12 volts in one position and zero in the other.

The switch comes in two electrical types and they are not interchangeable. Lippert's door switch guide lists a white normally closed switch used for all color controls, and a black normally open switch used for black controls since February 1999. Fitting the wrong one makes the step operate backwards, which the installation guide states directly. The switch itself is one of three shapes, a rectangular switch, a round switch, or a plated plunger, and where a magnet is used, the maker notes that its vertical placement is critical.

Kwikee's Coachstep manual carries a symptom and cause table. What it lists, and what it points to:

Two symptoms the makers do not map. No Lippert document ties a blown fuse to a specific cause; they publish the fuse ratings, a 6 amp in-line fuse and a 20 to 25 amp fuse or circuit breaker, and tell you to check them. And no maker document phrases the fault as working from the switch but not the door, or the other way round. The nearest published logic is the split above, plus the door switch voltage test.

Losing the ground stops the step completely. Kwikee states that the step will not function if the ground to the control unit is lost, either between the control unit and the vehicle chassis on the long green wire, or between the battery and the ground. A step that is dead with a good battery is worth a ground check before anything else.

And the step circuit has to be its own. Lippert's note is in capitals: the step wiring circuit must be independent, no other device such as an alarm system or a step well light can be connected to it, and any device connected to the step wiring can cause the step to malfunction and will void the warranty. The same document says not to splice or tap into any of the step wiring. A step that misbehaves after somebody added a light to the circuit is answering a question the maker already answered.

Lippert's position is that the step needs none. Its owner's manual and its own FAQ both state that the steps are equipped with self-lubricating bushings on the drive assembly and all step joints, and that no lubrication is necessary. It adds that if lubrication is deemed necessary in extreme conditions, a silicone based grease or spray will not harm the bushing material.

Its Tread Lite manual is more specific, and the specific part is the warning. That document says to use a dry silicone lubricant on the hinge areas between the sheet metal portions, and then states the reason: do not use a wet lubricant, because wet lubricants will attract dirt and possibly cause damage to the hinge areas.

Where the two meet. A dry silicone is the one product both of Lippert's own documents allow: the owner's manual says a silicone based grease or spray will not harm the bushing material, and the Tread Lite manual asks for a dry silicone and warns against a wet one. That is the safe choice if you lubricate at all.

What the documents do not support is the interval. The maintenance schedule on this site carries a 30 to 60 day step lubrication, and that interval comes from a coach manual rather than from the step maker. Lippert's own position on its electric steps is that no lubrication is necessary at all. A reader following the schedule is not doing harm with a dry silicone, but the schedule is a coach practice rather than a step requirement.

One more thing the maker asks you not to do. Kwikee states that adjusting the tightness of the step in the field is not recommended, that some minor movement is normal, and that excessive movement could indicate a more serious problem, in which case the bottom cover comes off for an inspection before anybody adjusts the cams.

The parts are catalogued separately, which decides what you buy. Lippert's parts guide lists the motor and the gearbox under separate part numbers, and notes that the gear and washers are not available separately from the gearbox, so a worn gear means the gearbox rather than a gear. The controller is sold as a replacement control unit, and Lippert's own product page for it carries a part number and no price, so the figure to work from is the dealer's rather than the factory's.

The labor is the reason to test first. The split above is a ten minute test with a meter, and it decides between a switch, a ground, a motor and a controller. Replacing any of them at random costs more than the meter.

The step is one of the things a pre-trip walkaround checks, and the walkaround guide carries the stow line for it. The maintenance schedule holds the lubrication interval and what it came from. And if the step is dead along with other 12 volt items, start at the 12 volt guide instead, because a shared ground is a different fault from a step fault.