The Classic Hymer Electric Step

The classic Hymer electric step is a powered platform located under the habitation door of the motorhome. It extends and retracts at the push of a button, making entry and exit easier. This article mainly concerns pre-1995 vans but also applies to a few post-1995 models.

Core Components

Step Motor and Cog Assembly:
A 12V electric motor drives a toothed cog engaging a matching toothed quadrant, which moves the step smoothly in and out.
12V Power:
The motor receives its 12V power directly from the motorhome’s battery to operate the step. The warning light and buzzer circuit are powered by the battery but only when the ignition key is turned on. This prevents unnecessary battery drain when the vehicle is off.
Step Operation Switch:
A Double Pole, Double Throw (DPDT) momentary switch controls the motor. The switch reverses the polarity of the 12V supply, so the motor spins in either direction—press one way to extend the step, the other to retract it.
Limit Switch:
Located at the top of the mechanism opposite the motor, this “open to make” limit switch operates a warning light on the dash. +12V (with ignition on) connects to one side, ground on the other. When the step is fully extended, closing the switch completes the circuit, lighting the warning light. When retracted, the switch opens and the light goes out. The switch is similar or identical to common motorcycle brake light switches; part numbers like Hella 937171 and Durite 05791 have been suggested by owners as suitable replacements.
Warning Buzzer and/or Light:
Alerts the driver if the vehicle is moved with the step extended. This differs by base model:
- In Fiat-based Classic Hymers, the existing Fiat brake warning light serves this purpose. Fiat owners often get confused by this because if they drive away with the step left down, the brake light remains on, making them think they have a brake problem. Fortunately, after a few instances, most get used to this.
- In Mercedes-based Classic Hymers, Hymer installed a separate, dedicated red warning light mounted on the dashboard or in the driver’s view. Unlike other Mercedes indicator lights, this light is unmarked with no symbols or text, illuminating only when the ignition is on and the step is extended.
- Buzzer: Some vans have a buzzer that operates alongside the warning light. These are usually dealer or owner modifications and are not part of the original factory setup.

Troubleshooting

Switch Wear
Switch failure is common after 20 or 30 years. Problems can be due to wear inside the switch or corrosion on the spade connectors. The switch is a standard rectangular DPDT (On)-Off-(On) momentary rocker switch (about 30mm x 22mm). For authentic replacements matching the original style, Marquardt (German-made) switches are recommended. Often, moving the spade connectors a few millimeters can clear corrosion and restore function.
Motor Failure
The 12V motor can fail mechanically or electrically. Hymer used a standard motor common in electric window systems. Compatible parts known to work include:
- Land Rover RTC 6640
- Land Rover RTC 3821
- Mercedes 0130821219
- Mercedes 0130821016
- Brose 187933-000
These motors have an 8-tooth cog; others with more teeth won’t fit correctly. A common failure cause is dirty water ingress. Many owners successfully strip, clean, and reassemble their motors to restore function. A helpful YouTube video titled "Hymer step motor" demonstrates this.
Blown Fuses
A blown fuse can cut power to the motor or warning system. The step motor is usually powered from the nearest habitation circuit. On pre-1995 models, this is often one of the top three fuses in the Hymer fuse panel. Later models with an EBL mark the step fuse as "Trittstufe" (German for step).
Quadrant Wear
Teeth on the quadrant can wear over time, causing jerky or irregular step movement. New quadrants are available but costly. Some owners repair this by welding and filing new teeth.
Exposure to Elements
Dirt, moisture, and grime cause corrosion and mechanical issues. Cleaning the step and wiring often restores operation.
Accidental Damage
Driving with the step extended can cause it to hit obstacles, pushing it out of alignment. Classic Hymer steps are solid steel and can often be repaired by hammering or bending back into shape.
Manual Retraction
If the motor or wiring fails, the step cannot retract electrically. To retract manually:
1. Remove the three bolts securing the motor.
2. Remove or secure the motor out of the way.
3. Push the step back up by hand.
4. Secure it with ties or straps.
Some owners find manual operation acceptable and convert the step by removing the motor entirely, allowing the step to drop by gravity and be pushed back up by hand. To hold it securely in the up position, a slide bolt or turnbuckle (available in hardware stores) can be fitted.
Red Warning Light Flickers or Stays On When Step Is Up
Usually caused by slight misalignment between the step and limit switch. Adjusting alignment typically fixes the issue.
Idiosyncratic Design: Random Intermittent Failure
The step sometimes refuses to operate despite everything appearing functional, causing frustration. The best remedy is to tap or vibrate the step near the motor while pressing the switch. Many owners carry a rubber mallet for this trick.

Summary

The classic Hymer electric step is a simple, if occasionally quirky, system: a battery-powered motor drives teeth to extend or retract the step, and a limit switch triggers a warning light if the step is out while driving. Mercedes models have a distinctive unmarked red warning light, Fiat models share the brake light, sometimes causing confusion. Common issues include worn switches, waterlogged motors, and intermittent electrical quirks. Many owners swear by a well-timed tap (rubber mallet optional) to keep it working. With some care and experience, this trusty step keeps you rolling… or at least trying to!

PHOTOS - in no particular order.