Electric step problem

[Hotrats13]

A teenzie weenzie small stone can and often does stop a step from retracting

 

[henrym]

Hi, my electric step no longer retracts when I start the engine. I have changed relays and problem still there. I noticed also that the lights, TV etc no longer cut out when engine is started. Any help would be very much appreciated. It is a Fiat Ducato Swift Lifestyle 2003 motorhome.

I had a similar problem with my Ford Hymer Van. The signal to retract the step, etc, comes from the lead from the alternator to the instrument panel that turns off the 'ignition' light. If the ignition light operates correctly, it's to do with what Swift have added.
Hymer broke into this lead near the alternator with a fused spur that goes to their control box. It's a 2 A fuse. When I checked it, it looked OK, but a digital voltmeter showed it was broken. It's so flimsy that taking it out probably cracked it.
Sorted that, power was getting to the lead but not the step controller.
The Ford (and Fiat) spec for this lead is probably just a trickle current to switch the ignition light. The switching your Swift is doing may need a greater current, which would effectively infringe the chassis manufacturer's T&C and invalidate their warranty.
For me, the lead leads to a 'current amplifier', a black box next to the leisure battery and Hymer control box. There was a voltage on the alternator side but not on the output side. It turned out that a fine connection within the current amplifier had failed, replaced by soldering in a length of fine fuse wire.