Iveco & VB Air Suspension.

[JockandRita]

Despite searching, I am unable to find any pointers as to my problem, so hoping someone reading this may be able to help.


Until a couple of weeks ago, our Iveco rear air suspension was working a treat, as was/is our front VB air suspension. Due to a complicated problem in previous years, the Iveco system was bypassed and isolated, and inflation now operates with the left switch on the VB control shown below. The right switch operates the front air bags.

I appear to have lost 12v power to the L/H switch, ie, no power at the terminals. Using the diagram below, both the 5A and the 40A fuses (which indicate they cover the rear suspension), are both sound using a meter to check for continuity.

I was then made aware of a "pressure regulator cut off valve", which I asked Iveco Boston about when there for my MOT yesterday. Their schematic diagram from the Iveco parts website, showed a valve, but had no description for it.


This morning with the MH raised on it's levelers, I ventured underneath on my crawler board and found this. Judging by the colour of the air pipes and it's relative newness, I assume it is a VB component rather than an Iveco one.

Hoping that this was the pressure regulator cut off valve mentioned, I investigated further. The red control appears to pull out for adjustment left or right, then pushes in with a slight click, and a locking feeling to the left. Unfortunately, neither position gave any results from the cab control, so it was placed back in it's original position.


I am no further forward, with no 12v power at the switch, and the very person who will know exactly what's what, (because he fitted the system himself), is on annual leave until next Thursday at the earliest.

Until his return, if anyone has any experience or knowledge on the reason for no 12v power at the switch, I'd be grateful for their input.

Fortunately, due to the foresight of the previous owner, In an emergency, I can inflate the rear suspension manually, by means of an installed Schrader valve.


Cheers,

Jock.

 

[JockandRita]

Bump.

 

[Jev88]

Completely different system Jock, but my air assist bags were playing up and not always responding to the switches. Replacing the main air compressor fixed it and it was only when I tested them with 12v side by side I could hear and feel the pressure difference put, put putting out of the tube.
I had to borrow a widget to do a longer distance continuity test on the wires to the switch.

 

[JockandRita]

Thanks Jev.

Weather pending, I'll get under there again and check the connections/continuity at the compressor, which is the original Iveco one.

With there being no 12v at the switch, I can't help thinking it's a blown fuse somewhere.

Cheers,

Jock.

 

[Terry]

On my Iveco the air suspension was controlled by 3 relays under drivers seat -I assumed one to turn air compressor on one to turn it alongside one that released the pressure after pressing a switch. I could also adjust the pressure (firm/soft) for ride with a red knob on side of seat. I found out my problem was down to one of the relays-swapped and worked Then a couple of years later found out that if I turned down the red knob (soft) it would kick in the relay to pump air and once started simply turned knob to where I wanted it —kept van for 8 1/2years problem free

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[Steve and Denise]

On our Jock the VB air on the front is controlled directly by the switch ie no electrical connection on the switch but just two air pipes, one in one out T to the pressure gauge pipe straight to the air bags for high/pressure,
but the rear still has the Iveco system controlling it from the three buttons on the r/h side of the dash.
I did have a compressor issue when I first got the van but that was just a pressure switch.

 

[Ditcha]

The 3rd photo is a pneumatic pressure relief valve, if I remember rightly turn clockwise to increase pressure, anticlockwise to decrease pressure can't tell from the photo wether or not it is connected to a pressure switch or not.

 

[JockandRita]

but the rear still has the Iveco system controlling it from the three buttons on the r/h side of the dash.

Thanks Steve and others, for your input.

Prior to my ownership, there was a problem with the Iveco system, which was put down to a possible faulty PCB. The expensive replacement PCB however wasn't guaranteed to fix the problem, so an alternative solution was found. This meant the isolation of 3 x Iveco control buttons, in favour of a VB control, (see left switch on image one), which does have a couple of wires with spade type connectors to it...................but no power.

SAP (whom I am led to believe fitted the modification), eventually returned my call yesterday having looked at the email with photos. The best they could say was, "Pop it in and we'll have a look at it."

Cheers,

Jock.

 

[JockandRita]

At last, and with the help of the previous owner Martin at Hereford, the culprit has been identified. A replacement Relay Repair Kit has been advised................

...............with one being sourced locally................but.............

............. as I have neither the skill nor the proper tools to to the job myself, help is coming sometime soon..........hopefully.
The repair needs to be water and corrosion proof, by cutting back to good wiring, then creating new joints, replacing old corroded ones.

funflair. Martin, the yellow and white wires go all the way back to the rear axle, but the joint from the yellow one to the relay, was continued in brown. No wonder we struggled with that one.

Cheers,

Jock.

 

[funflair]

As long as you are getting sorted Jock, that wire changes colour a couple of times on it’s journey and then disappears into a taped up bundle but when I saw the melted one I stopped looking much further.

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[JockandRita]

As long as you are getting sorted Jock, that wire changes colour a couple of times on it’s journey and then disappears into a taped up bundle but when I saw the melted one I stopped looking much further.

Thanks Martin.

It's only melted to just under that insulation tape nearest the relay, and not all the way along to the last joint, which I was really relieved about.

Cheers,

Jock.

 

[JockandRita]

UPDATE......................

All sorted now, with the help from a couple of great Auto Electricians. One replaced the wiring making new joints to the new relay holder, and insulated them all, before installing the new relay. The other searched for an interruption to the power supply, and found 2 x 40A fuses inside the engine compartment, which I was unaware of. One was blown, so once replaced, we were back up and running with both compressors. Old relay tested and found to be okay, so that'll be kept as a spare.

Today's repair has not only restored the ability to inflate/deflate the rear air bags remotely, but it has also saved me a journey up to Doncaster, whereupon SAP's books are already full with bookings. Via email, both Mick and Rachel at SAP were helpful with information re parts required, leading to the repair.

Cheers,

Jock.

 

[funflair]

Nice on Jock

 

[JockandRita]

Nice on Jock

Thanks Martin, and thank you for your efforts at Hereford, to help establish the problem. Much appreciated.

Cheers,

Jock.