Technical Our step no longer retracts automatically on ignition any ideas of where to look?

[Communicator]

The buzzer is (conventionally) wired in parallel to the step-retraction circuit, so I think it's lack of working is a symptom, rather than a cause, of the problem. It could be located anywhere, but I'd think the engine compartment is unlikely. Common locations are under either the driver's or passenger's seat, or, if the kitchen is near the habitation door, behind the kitchen drawers or cupboard. Generally a small black unit.

I'm pretty sure there are two relays, one for split charge, and one for fridge 12v, the latter also supplying the step retraction*. I don't think we've yet been told whether fridge 12v is actually working. Since the problem doesn't appear to be the dodgy fuse box, I'd want to check the 15A fuse position for 12V when the engine is running. It's relatively easy to access, and focuses the next step(s).

If 12v is present (and the fridge is OK), then the issue is in the wiring from the fuses to the step, or the step internal controls/relay. If 12v is not present, then you're looking at the circuit upstream of the fusebox, the wiring, the relay and the D+ signal from the alternator.

*It appears that the EMC relay is also fed from the same relay/fuse as the step. If it hasn't been messed with (as sometimes people have), a significant amount of the internal lighting should go off with the engine running. If this happens then it confirms there is power through to the 15A fuse in the fusebox.

In clarification of Hugh's post, the buzzer is wired in parallel with the step (retract) relay coil. The fact that the buzzer is not working suggests that the step relay is also unlikely to be working.

For further clarification there are two relays involved with the step operation. As stated in my post #5 above the the fridge relay is operated from D+ (alternator field circuit). D+ is a low current supply which becomes live when the engine is started, and the alternator starts generating power. In order to avoid taking to much power from the D+ point, the supply to the step relay coil supply is connected to the output (fridge side) of the fridge relay. The step relay may be mounted close to the step (mine is under the kitchen sink), and hence separate from the fridge and split charge relays.

 

[Communicator]

Due possibly to the lateness of the hour, I forgot to add an intended comment about the step limit switch. On some modela electric steps, the limot switch was exposed at the rear of the step, and prone to corrosion by road spray. If the connection fails the step will not auto retract, and the warning buzzer will not sound. The manual switch will function as normal.

If the step is an"Omnistep" the motor unit will have four wires. Orange and voilet for the motor, and grey plus brown for the limit switch. As the step is working from the switch, the orange & violet wires must be functional. Either of the grey or brown wires must be connected to chassis, and the remaining wire must be connected to the negative side of the step relay coil, and the warning buzzer.

 

[GrumpyGran]

UPDATE Step etc now working Thank you all for all your wonderful help.

It was a corroded connector coming from the vehicle battery. OH has been checking terminals and we were suspecting the split charge relays as there was power from under the connectors but nothing at the relays. So he back tracked and found a connector he'd missed.

Didn't realise he'd fixed it at that point so made us jump when the buzzer sounded and the step slammed shut.

I'm now seriously doubting that the fridge could have been working on 12v but at the same time know that I've checked in the ice box when we stopped for a tea break or dinner, and its always been frosty, with no signs of defrosting. I'm wondering if the fused and corroded contact under the 15 amp fridge fuse ( before we replaced the box) was picking up power from another wire?? Having completed the other work yesterday he took it for a run around the block and the fridge wasn't working on 12v at that point, I had a thermometer in there but it didn't move at all. So todays success was a relief all round.

The step wiring was under the cupboard next to the habitation door as expected but completely different colours (grey orange and purple). I think we have a cross over year for wiring. We have a distribution panel from the sundance/bessacarr diagram but fuses boxes (from wardrobe) as detailed on the kontiki/bessacarr diagram. But either way the diagrams have helped us find our way around the electrical system so not as scary as first thought.

As a bonus the alarm is now working.!!

 

[GrumpyGran]

Due possibly to the lateness of the hour, I forgot to add an intended comment about the step limit switch. On some modela electric steps, the limot switch was exposed at the rear of the step, and prone to corrosion by road spray. If the connection fails the step will not auto retract, and the warning buzzer will not sound. The manual switch will function as normal.

If the step is an"Omnistep" the motor unit will have four wires. Orange and voilet for the motor, and grey plus brown for the limit switch. As the step is working from the switch, the orange & violet wires must be functional. Either of the grey or brown wires must be connected to chassis, and the remaining wire must be connected to the negative side of the step relay coil, and the warning buzzer.

Yes it is an Omnistep so that explains the wiring colours.

 

[GrumpyGran]

We are thinking that we should try and pick up a few spare relays for future problems? There are 2 split charge relays marked with 010405 (30,85,86.87) but the ones I've found (with corresponding numbers and diagram) do not have 4 blade connections. The new ones seem to have 2 blades then 2 screw terminals so that would be a case of also replacing the connector blocks they fit into.

Is it still possible to buy the original type and if so where is the best place to get them??

 

[HughJampton]

Glad you've managed to sort it. I spent a long time helping someone with a similar problem, eliminating all other possibilities until a broken wire was found behind the vehicle battery.

If you feel you need some, the relays are readily/widely available with 4 pins. 12voltplanet and Vehiclewiringproducts are two sources I've used that have them, but frankly, eBay should suffice. They're standard N/O ones.

Since the fuses are at 15/20A, 20A relays are the minimum you should use (I'd probably look for somewhat higher) and be aware that, though the terminals are annotated the same, there are two pin layouts (type A and Type B) which fit different sockets (plenty of diagrams as to which is which on the web), so you need the same layout as you have.

 

[Communicator]

GrumpyGran,

Please do not panic. As I read your posts, you have not had a relay failure. What you have suffered from is corroded connections to the relays and battery. The best way to combat any reoccurance is with a small smear of vaseline applied to the connectors, so as to exclude moisture, which close to the battery could be acid laden. In winter, or in coastal areas, any moisture could be salty. Both circumstances will tend to cause corrosion.

The split charge relay is vital for charging the habitation batteries, when you exclude solar panels, and EHU. As regards the fridge relay, you seem to have been managing without the fridge 12V element supply. The split charge, and fridge relays would be interchangeable in an emergency.

The step relay is different, having 5 pins, and would need a dedicated spare. You cannot move the step, if the relay is removed on faulty between coterminals 30 & 87a.

The most onerous task for a relay is to interrupt full load current flowing into a motor (step motor), or solenoid which you don't have. The split charge and fridge relays both interrupt a flow of electrisity when the engine is switched off, and the current (flow of electricity has already decreased by a large amount, therefore relay contact failure is not very likely.

You have not said what version of Fiat 2.8 engine you have. If post 2000, it will probably be a 2.8JTD, and will have several better protcted relays either under the bonnet or in the dashbord. If some of these relays fail the engine will not run, or you could just lose headlights or horn. relays can't be that unreliable can they?

The decision is yours. Some of the numbers. 86, 85, 30, & 87 are the relay terminal designations, The step relay will also have 87a.

86 Operating coil positive.
85 Operating coil nagative.
30 Common or supply contact (C).
87 Normally Open contact (NO).
87a Normally Closed contact (NC).

The positive and negative connections to 86 and 85 respectively, are not always observed, but some relays will blow the supply fuse if the connections are not correct.

Should you decide to buy a spare relay, why not consider a five blade changeover relay, provided that it will plug into the base, it could serve in all three roles.

 

[HughJampton]

I carry the odd spare part (notably a submersible water pump) when such things are going to be disruptive if they fail, and aren't going to be readily available, and also a number of lengths of wire, fuses, etc. which allow me to bodge critical things.

The relays in question, however, aren't absolutely critical, and are widely available from most motor part stores with no notice (even Halfords!). Unless you have reason to suspect an imminent failure, I think I'd just be happy you've resolved your immediate issue, and forget it.

 

[GrumpyGran]

I had already looked on ebay but all I'm finding are heavy duty ones (70 -100amp) ones with the wrong connections. We cant afford a new MH so trying to be a bit forward thinking for future repairs. Will try halfords or europarts? (our main source up here) to see if they are still able to get them, though I have found with these larger companies they show as in stock until you actually try and place the order.

A lot of the these parts (or their components) come out from china, and supplies are just not getting into the UK. We've hit lucky a few times and managed to source what seems to be the last item in the UK, with multiple outlets reporting long delays or no idea if and when there would be stock available online a few days later.

We bought the newer version of the reich shower to replace our leaking crumbling one back in january and it immediately showed out of stock across multiple outlets (all presumably using the same supplier), and is still out of stock now. There are plenty of cheap kitchen sink mixers (sold as sink/shower) but they are the wrong shape and the water angle is not the same.

 

[GrumpyGran]

Should you decide to buy a spare relay, why not consider a five blade changeover relay, provided that it will plug into the base, it could serve in all three roles.

Thats useful to know. I'd assumed I might cause some damage if I fitted a 5 blade one where a 4 blade was originally, so didn't try it.

 

[Communicator]

Thats useful to know. I'd assumed I might cause some damage if I fitted a 5 blade one where a 4 blade was originally, so didn't try it.

No way will it cause damage, provided that the socket will physically accept and shroud the fifth pin (87a). No electrical connection required there except for step relay.

Perhaps you used the wrong search term on Ebay. Here is a link to a search made a few minutes ago.

However I would probably not bother. I have diagnosed, and read of step problems on other forums. I cannot remember the relay being a problem. More often it was corrosion problems similar to yours. While on this forum I can only remeber one probable relay fault, and that was for the base vehicle heater fan, which takes a relatively high current

 

[GrumpyGran]

No way will it cause damage, provided that the socket will physically accept and shroud the fifth pin (87a). No electrical connection required there except for step relay.

Perhaps you used the wrong search term on Ebay. Here is a link to a search made a few minutes ago.

However I would probably not bother. I have diagnosed, and read of step problems on other forums. I cannot remember the relay being a problem. More often it was corrosion problems similar to yours. While on this forum I can only remeber one probable relay fault, and that was for the base vehicle heater fan, which takes a relatively high current

I put in "motorhome split charge relay" as a search term which wasn't that helpful.

I've just double checked the fridge on 12v and its working OK, also the interior lights go off on engine start.

 

[Communicator]

So all good now.

I had already looked on ebay but all I'm finding are heavy duty ones (70 -100amp) ones with the wrong connections. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Relays rated at 120A or even more, and with 6mm (M6) terminal studs are somtimes used in conjunction with thicker cables up to 25 sq mm to increase the charging current flowing into the habitation battery from the alternator, and hence reduce that batteries recharging time. That does not mean that you will get 120A flowing into the habitation battery. It would not like it! The thicker cables and bigger relay reduce the electrical resistance by a small amount which allows a greater current to flow.

"But either way the diagrams have helped us find our way around the electrical system so not as scary as first thought."

If its any consolation, as to the diagrams being scary, I think that they are not easy to follow. They are "wiring diagrams", which show you where the wires go but, are not much use when trying to understand how the system is supposed to function. I much prefer routed schematic diagrams which show where wires are actually connected, as well as how the step or whatever works, and hence what has gone wrong.

 

[CeriR]

Had the same problem on our 2002 Ducato but fridge also not working, the 2 relays and fuses were located on the inner wing drivers side behind the battery, all the connectors were corroded! Replaced the entire thing and fitted new crimp spades to the wires, step and fridge working again.

Did you have any issues (what precautions did you take) when removing the starter battery in regards to the immobilizer and red key?