Kwikee Series 42 Heavy-Duty Double Electric Step (Lippert)

Overview

The Series 42 is Kwikee's heavy-duty double entry step for coaches, current-generation (post-2005) units using the IMGL integrated motor/gearbox/linkage and a separate control unit. The control unit is fundamentally a current sensor and switch: it drives the permanent-magnet motor until the step reaches its mechanical stop (or hits an obstruction like a kerb), sees the current spike, and cuts power. There are no position switches to adjust — which also means a binding or bent linkage reads to the controller exactly like end-of-travel, producing the classic 'extends part way and quits' complaint.

Two logic features protect the coach: ignition override — with the door closed and the ignition switched on, the step retracts even if the override switch is holding it out, so the coach is not driven with the step extended; and auto-extend — the first door opening after the ignition goes off always extends the step regardless of the override switch, so nobody steps out into fresh air. With the ignition on, the step always follows the door. Note the corollary warning posted on the step: turning the ignition on with the door closed retracts the step — visually confirm the step is out before exiting.

Wiring essentials

The step connects through a four-way connector plus a two-way motor connector:

• Red (12 AWG) — battery power, 20 A fuse or breaker.
• Brown (16 AWG) — door switch input; grounded = door closed = retract (normally-open magnetic door switch).
• White (16 AWG) — override switch; +12 V holds the step out with the door closed (6 A max fuse in that circuit).
• Yellow (16 AWG) — ignition input; must land on a terminal hot only with the ignition on, or the ignition-override safety is dead and the step will sit extended.
• Green (12 AWG) — ground, securely fastened to the chassis with clean metal-to-metal contact. Most erratic behaviour is a ground problem.

Hard rules from Lippert: the step circuit must be independent — wiring alarms, step-well lights or anything else into it can cause malfunctions and voids the warranty (the under-step light gets its own 1 A fused feed from the porch-light switch via the purple wire). If the coach feeds the step from a converter instead of a battery, the converter must supply a clean 30 A minimum. A healthy battery reads about 12.6 V no-load; low or dirty supply voltage produces part-way travel and random stops. Expect a small spark when reconnecting step power — that is the control unit charging, not a fault.

Bench-style step test (isolates step from coach wiring)

With a charged 12 V battery and a four-way pigtail (Lippert 369243) plugged into the step half of the connector, ground the green wire to the battery negative and feed red to positive — the step extends. Then: brown to negative = retract, remove brown = extend; white to positive with brown held to negative, then yellow touched to positive = step retracts (ignition override works); remove brown = extends again. If every function passes on the pigtail, the fault is in the door switch, override switch or coach wiring; if any fail, it is the control unit or motor.

Motor test: disconnect the two-way connector; motor yellow to battery positive and red brushed to negative = extend; reverse = retract. Remove the wires as soon as the step completes travel — leaving a stalled motor connected burns it out and voids the warranty. Control unit shutoff test: with the motor two-way disconnected, meter across the control unit's red and yellow motor outputs and turn the override on: any voltage persisting beyond five seconds means the control unit is not shutting off and is likely defective (pull the four-way to protect the motor).

Voltmeter quick checks at the coach half of the four-way (against the green ground): red ≥12 V always; white 12 V with override on, 0 off; red-to-brown 12 V door closed, 0 door open; yellow 12 V ignition on, 0 off. On door-switch-only steps the white wire must read 0 V — if it shows 12 V it is miswired and should be cut.

Extension stop adjustment (step feels loose)

Adjustable extension stops on the frame lock the extended step into a firm platform; shipping and use knock them out, and the symptom is a step that flexes or clunks underfoot. To reset: loosen both stops and retract the step; extend fully and confirm the motor linkage rests against its steel plate (re-run extension until it locks fully out); push both stops firmly against the lower tread and tighten; retract and confirm both stops seat against the top tread. Always make sure the step cannot activate while hands are inside the mechanism — pull power, not just the door switch.

Maintenance

Clean first, then lubricate: power-wash mud, salt and road grime off, then spray dry lubricant on the bearings both sides of the step. Lippert specifically recommends against silicone sprays and WD-40 — they evaporate and leave the mating surfaces dry and exposed. Keep the two-way and four-way connectors clean and dry with a dab of dielectric grease; replace corroded butt splices with heat-shrink crimp connectors. In salt environments, rinse the step with fresh water routinely to preserve the finish. There is no scheduled parts replacement — the step lives or dies by clean power, a good ground, and clean, dry-lubed pivots.

Related: lift interlocks

Farber coaches with wheelchair lifts also carry an InPower ITM126 lift interlock module — that unit gates the platform lift, not the entry step, and is covered in the Braun NUVL855R lift article.