Technical Omnistep problem

[Communicator]

According to the diagrams, there should be a red wire from the starter battery positive, to maxi fuse, brown to 4 way block fuse 4, and brown/green thereafter. So converter has not adhered to diagram. You have brown/green wires leaving the 4 way block that are live at 12V,, but 12V is not present on brown/green?? wire at stap switch. (Please confirm that brown/green wire arrives at step switch, as in diagrams.
You also had partly melted fuse holders. How do the wire(s) get from the 4 way block to control panel, and step switch. How many brown/green wires are connected to the load side of fuse 4, one or two?

At this stage you have to consider the possibility of damaged wires, either trapped inside the vehicle, or abraded underneath the vehicle.

It is possible but not certain that your loss of starter battery voltage reading at the control panel is due to a resistive fault. Meter reads OK with no load. but if the step is trying to auto retract with buzzer sounding, then the voltage could collapse. (The step buzzer is powered from D+ in parallel with the step relay.)

If there is a problem with the maxi fuse holder then It would probably have signs of overheating.

Sorry, I got that bit wrong. I should have checked the diagram. On the Sargent system, power for the step buzzer, step relay, and auto retraction are taken from the fridge 12V element supply, which is controlled by the D+ signal, and hence is only live when the engine is running. This also affects my idea about the step trying to retract.

I am trying to save your wallet from excessive expenditure. As requested, can you confirm that a brown/green wire arrives at the step switch?

How many similar brown/green wires are connected to the ouput side of fuse 4 on the 4 way block?

I ask because I am trying to understand where the wires join together.

 

[Neilmay]

Sorry, I got that bit wrong. I should have checked the diagram. On the Sargent system, power for the step buzzer, step relay, and auto retraction are taken from the fridge 12V element supply, which is controlled by the D+ signal, and hence is only live when the engine is running. This also affects my idea about the step trying to retract.

I am trying to save your wallet from excessive expenditure. As requested, can you confirm that a brown/green wire arrives at the step switch?

How many similar brown/green wires are connected to the ouput side of fuse 4 on the 4 way block?

I ask because I am trying to understand where the wires join together.

Hi, i have attached photos of maxi fuse, there is resistance and voltage. Fuse holder with brown wire and brown/green to bottom fuse (blue 15a) others are 20a fuses, one spare. Switch shows green brown wire.

 

[Communicator]

Hi, i have attached photos of maxi fuse, there is resistance and voltage. Fuse holder with brown wire and brown/green to bottom fuse (blue 15a) others are 20a fuses, one spare. Switch shows green brown wire.

Hi Neil,
Thanks for the photos. The maxi fuse has one thicker brown wire, which is presumably the connection to the battery. (Diagram shows red,) There are two output wires, one to the split charge relay, and one to fuse 4. This matches diagram so OK so far.

The output, or load side of fuse 4, has only one brown/green wire. The diagram shows two brown/green wires, one to the step switch, and one to the distribution/control panel. As the step connection is not at fuse 4, then the only other obvious place is at the distribution panel. This would make sense, as the distribution panel will be closer to step, than fuse 4.

I suggest that checking the connections at the distribution panel is the next move to make. You are looking for two brown/green wires at the distributin panel. One from fuse4, and the other going to the step switch.

Good hunting.

 

[Communicator]

@Neilmay any resolution?

 

[Neilmay]

@Neilmay any resolution?

Hmmmmmm, away for weekenf and lo and behold the display shows power from leisure and starter battery???? No luck with power to step1

 

[Communicator]

Hmmmmmm, away for weekenf and lo and behold the display shows power from leisure and starter battery???? No luck with power to step1

As I suggested in post #23, your next move should be to check for two brown/green wires connecting together at the control panel. Perhaps one has become disconnected. The only other possibility that comes to mind, is a 3 way connection somewhere in the wiring run. (Fiat make similar connections in base vehicle cable wiring harnesses.)

I cannot help you any further with your problem.