Habitation Electrics not Working - Carioca 644

[AL68]

I have a 2005 CI Carioca 644. During a trip to France in May we lost the engine charge to the leisure battery. On returning to UK our dealer found the fault to be a poor connection in the control unit mounted behind the driver seat; fixed under warranty. No problems thereafter during 3000 miles around Europe in October. Recently checking van over and found that we have no 12 volt electrics in the Habitation side. Have checked all fuses i could find but still no electric. Have dismantled the control unit that distributes 12 volt power and can confirm that 12.7 volts is arriving from engine and leisure battery. The D+ voltage is around 25 volts and the alternator supply rises to 13.7 volts on starting the engine. So no 12 volt fridge, lights, water pump, leisure battery charge, etc.

 

Is it the circuit board and components? I understand this could be a £300 bill and delivery of a new board could take 6 weeks. Have been looking at bypassing this 21 century technology, is it really necessary?

 

Alan (?)

[Dave Newell]

Hi Al, I'm a bit concerned about your D+ voltage rising to 25V, it should only ever get to 13.8-14.4, if it really is going to 25V then you have a faulty voltage reg in the alternator.

 

Now to your failed hab electrics, I had a 05 reg Carioca in a couple of days ago with exactly this problem, a few checks and some internet research reveal this to be a not uncommon issue and it is usually caused by the control panel over the door failing. Sometimes disconnecting it for 30 secs will revive it but not for my customer. Geoff Cox motorhomes have ordered a new control panel for us at about £150 plus VAT and about two weeks delivery from Italy.

 

D.

[Brambles]

Where are you checking the D+ voltage as I suspect you getting a reading of 2.5 volts or even 0.25 volts and not 25 volts. If this is the case then your split charge relays will not be operating. You maybe have a bad conection for the D+ to the control box behind the seat or a fuse has blown in this cable connection to the base vehicle electrics (fiat???) somewhere around the fuse box lower left hand side of dash (2 srews holds cover in place).

[AL68]

I will have to check that voltage on D+, perhaps it was 2.5 and not 25 volts. Also make sure that I was checking incoming D+.

 

Interesting that you think it might be the switch panel over the door. How can I check that it is the switch panel and not the main board in the control unit?

 

I am still looking for other causes but heavy snow has slowed this down a bit.

 

Thanks

[AL68]

Dave Newell - 2010-12-01 5:46 PM

 

Hi Al, I'm a bit concerned about your D+ voltage rising to 25V, it should only ever get to 13.8-14.4, if it really is going to 25V then you have a faulty voltage reg in the alternator.

 

Now to your failed hab electrics, I had a 05 reg Carioca in a couple of days ago with exactly this problem, a few checks and some internet research reveal this to be a not uncommon issue and it is usually caused by the control panel over the door failing. Sometimes disconnecting it for 30 secs will revive it but not for my customer. Geoff Cox motorhomes have ordered a new control panel for us at about £150 plus VAT and about two weeks delivery from Italy.

 

D.

 

 

The snow has been washed away in east Kent and i have now checked the D+ voltage which is around the 14V region. Where i got 25 volts is a mystery. Looks like I will have to get to a CI expert / dealer to identify the problem.

 

Thanks

[rupert123]

The thing Dave suggested is worth checking. Disconnect all electric supply to habitation, hookup, leisure battery for a short period then re connect, it may well re-set.

[AL68]

rupert123 - 2010-12-06 11:27 AM

 

The thing Dave suggested is worth checking. Disconnect all electric supply to habitation, hookup, leisure battery for a short period then re connect, it may well re-set.

 

I have done this a couple of times if not more while carrying out checks. I unplugged everything from the control unit behind the driver seat and took it into the house, similarly with the display panel fixed above the door. I took photographs of them to send to a an electronics business that claimed to be able to repair printed circuit boards. Since then they have been back in place, Today I disconnected both battery supplies too the main pcb to check incoming voltages. Also took out the display panel again. All reassembled but still "dead". Anything that relies on this control unit is not working including habitation battery charging and 12 volt fridge supply when the engine is running.

[AL68]

AL68 - 2010-12-01 5:06 PM

 

I have a 2005 CI Carioca 644. During a trip to France in May we lost the engine charge to the leisure battery. On returning to UK our dealer found the fault to be a poor connection in the control unit mounted behind the driver seat; fixed under warranty. No problems thereafter during 3000 miles around Europe in October. Recently checking van over and found that we have no 12 volt electrics in the Habitation side. Have checked all fuses i could find but still no electric. Have dismantled the control unit that distributes 12 volt power and can confirm that 12.7 volts is arriving from engine and leisure battery. The D+ voltage is around 25 volts and the alternator supply rises to 13.7 volts on starting the engine. So no 12 volt fridge, lights, water pump, leisure battery charge, etc.

 

Is it the circuit board and components? I understand this could be a £300 bill and delivery of a new board could take 6 weeks. Have been looking at bypassing this 21 century technology, is it really necessary?

 

Alan (?)

 

Interested to know if anyone has abandoned existing central electronic control units. The problem with them is that if they fail nothing works and sourcing replacement parts can take a long time. Where does that leave you when it happens on the road?

 

[Brambles]

Next step, Check all your Zero volt connections are good. It is all too easy to miss this one.

 

After that the next thing to concentrate on the the fridge and split charge relays. These are simple circuits which just happen to reside on the same PCB comtrolling more intelligent feaures like switching lights on and off etc. The control panel being dead should not affect Battery charging or the fridge, the fact they are not working probably being why the control panel is not working such as a break in a common supply track on the PCB , fuse or external wiring. Check fuses with a meter not just visually.

[Brambles]

AL68 - 2010-12-06 12:35 PM

 

Interested to know if anyone has abandoned existing central electronic control units. The problem with them is that if they fail nothing works and sourcing replacement parts can take a long time. Where does that leave you when it happens on the road?

 

Up the creek without a paddle.

Just have to hard wire new split charge relays for battery and fridge along with switches for lights and other circuits. Any auto electrician should know how to do this.

[AL68]

I purchased a new power distribution board and control panel from a CI dealer for a very reasonable price. Unfortunately, fitting these has not solved the problem. I have, however, learnt quite a lot about the workings of the power distribution board! There is an auxilliary fuse and terminal that can be used to run the water pump. Useful to know if the problem crops up again after it is fixed.

 

However, I am still looking for the cause of the fault so any ideas welcome.

 

 

 

Brambles - 2010-12-06 1:35 PM

 

AL68 - 2010-12-06 12:35 PM

 

Interested to know if anyone has abandoned existing central electronic control units. The problem with them is that if they fail nothing works and sourcing replacement parts can take a long time. Where does that leave you when it happens on the road?

 

Up the creek without a paddle.

Just have to hard wire new split charge relays for battery and fridge along with switches for lights and other circuits. Any auto electrician should know how to do this.

[Brian Kirby]

Alan

You are sure 12V is getting to the board from the leisure battery, and the leisure battery is healthy?  If so, it can't be the main12V fuse at the battery.

Notwithstanding, you have no 12V power out of the board?  No lights, no heater, no pump? 

That sounds a bit as if the main 12V power relay is in the "off" position.  In that position, it will allow battery charging, but isolates all downstream functions except fridge and electric step (if fitted).  However, you have replaced the board plus control panel, so any fault on the existing panel should have been eliminated - unless the main 12V power relay is not mounted on the board, and the original is still present. 

Ours has two or three relays mounted within the power unit casing, but not on the PC board.  Might your relay possibly be in a different (but probably nearby) location?  Might it even be a detached wire on that relay?

[AL68]

Brian, You have summed up correctly bar two points which may be because i have given incorrect information previously; the 12 Volt fridge does not work but the heating does work. I can see from the circuit diagram that anything that has a relay involved will not work, which includes the fridge but not the heating. I have bridged the supply and load sides of the relays for the lights and water pump with a home made link fabricated from 2.5 mm2 copper wire, sure enough the lights come on and the pump functions. The relays are not being switched but why not? As far as I can ascertain all of the relays are on the power distribution board. I will look to see if i can find anything else.thanks for your thoughtsAlan

Brian Kirby - 2011-02-01 5:41 PM

Alan

You are sure 12V is getting to the board from the leisure battery, and the leisure battery is healthy?  If so, it can't be the main12V fuse at the battery.

Notwithstanding, you have no 12V power out of the board?  No lights, no heater, no pump? 

That sounds a bit as if the main 12V power relay is in the "off" position.  In that position, it will allow battery charging, but isolates all downstream functions except fridge and electric step (if fitted).  However, you have replaced the board plus control panel, so any fault on the existing panel should have been eliminated - unless the main 12V power relay is not mounted on the board, and the original is still present. 

Ours has two or three relays mounted within the power unit casing, but not on the PC board.  Might your relay possibly be in a different (but probably nearby) location?  Might it even be a detached wire on that relay?

[Brambles]

So it sounds like for some reason the relays are not getting energised. Could be three reasons. 1. The 12 volts to the coils is switched off because the system wrongly detects low battery volts or the control panel detects low volts. The other reason is there is no 12 volts supply as a link somewhere is broken be it a fuse or broken circuit. Third reason is the control panel cannot communicate with the control box via the 4 way serial cable as it has breaks.

 

I would check the 4 way cable to the control panel at both ends. Very easy to do. Unplug both ends. Check no shorts between any combination of wires. Next at one end short two together and the remaining two together. At other end with meter check the shorted pairs are shorted.

 

 

 

[AL68]

I have checked the 4 way cable to some degree in the past. I checked continuity of each cable though in a slightly different manner than you suggest using a long length of cable between each end of the 4 way cable and a multimeter. Your method sounds easier!

There is 13 volts (I am using mains supply at the moment having isolated the service and vehicle batteries in case they have low volts) between brown and all wires except green which has 0 volts between it and brown. Whether this is right or wrong I don't know. I will check for shorts between the 4 cables tomorrow. As I understand it, two cables are used to supply power and the other (middle) two are the bus wires for communications between display and power distribution board. The trigger to switch the relays. Presume there must be a processor to send and interpret the information in the bus wires.

 

 

 

Brambles - 2011-02-03 5:23 PM

 

So it sounds like for some reason the relays are not getting energised. Could be three reasons. 1. The 12 volts to the coils is switched off because the system wrongly detects low battery volts or the control panel detects low volts. The other reason is there is no 12 volts supply as a link somewhere is broken be it a fuse or broken circuit. Third reason is the control panel cannot communicate with the control box via the 4 way serial cable as it has breaks.

 

I would check the 4 way cable to the control panel at both ends. Very easy to do. Unplug both ends. Check no shorts between any combination of wires. Next at one end short two together and the remaining two together. At other end with meter check the shorted pairs are shorted.

 

 

[Brambles]

Yes to to the bus wires. Check as you said you would for shorts, and check you have zero volts to the control (relay) unit.

 

[AL68]

Brambles - 2011-02-03 8:59 PM

 

Yes to to the bus wires. Check as you said you would for shorts, and check you have zero volts to the control (relay) unit.

 

Brambles

 

I have now checked the four way connection cable for continuity again and for short circuits between any combination of wires. All is in order with no faults detected.

 

I am not sure what you mean by zero volts to the control (relay) unit? Do you mean generally on the power distribution board or at a particular switching relay? What is the objective, to see if there is a short circuit?

 

I am going to have another look at the circuit diagram for the distribution board to see if I can devise some more checks.

 

Thanks

 

Alan

 

 

[Brambles]

I mean check you actually have a ground connection to all appropriate parts of the distributon board ( the one with the relays). It is always worth checking zero volt connections are conected just as you do 12 volts.

 

Can you tell me what model panel etc you have and I will see if I can find a cct diagram for you, unless you already have one.

 

Edit - Ahhhh, you have a cct diagram, let me know what model panel and make, just to make sure I am looking at same thing.

[AL68]

Brambles - 2011-02-04 9:17 AM

 

I mean check you actually have a ground connection to all appropriate parts of the distributon board ( the one with the relays). It is always worth checking zero volt connections are conected just as you do 12 volts.

 

Can you tell me what model panel etc you have and I will see if I can find a cct diagram for you, unless you already have one.

 

Edit - Ahhhh, you have a cct diagram, let me know what model panel and make, just to make sure I am looking at same thing.

 

I have checked a number of tracks on the pcb and these are earthed.

 

 

I am working from the manual supplied with the motorhome. The company who make the board, ArSilicii, supply a manual with the ref TTK.D10F/CP5L22. It has a diagram but is not very clear and quite small. I have therefore put this into Google and retrieved the manual in pdf format (http://www.arsilicii.com/public/Documents/AS00029_SC.pdf) . However, the online manual is for a version 7 board. Mine is a version 5 board. The differences are not that great. CT6 is only a one terminal connection rather than 4 as shown and nothing connected to it. The CT7 connection and wiring is not shown on the version 5 board. CT9 and CT10 power the heating / hot water. CT8 is the Step. Nothing connected to CT5. No info on J7. J2 is the fresh water tank sensor. J3 is for another tank if fitted so not connected. J6 is the waste water tank level. J4 is the bus to the control panel. J5 no info.

 

I think that is about it.

 

Thanks again

 

Alan

[Brian Kirby]

Backtracking a bit, the first fault was failure of charge to the leisure battery from the alternator.  Fixed by dealer.  Method unknown/unstated.

You now find you have no 12V outputs from your main board (except to heater), but have confirmed 12V in from leisure battery (which is healthy), and from the starter battery.  I'm a bit puzzled by that supply from the starter battery, as it should be isolated by a relay unless the engine is running.  Is it live with the engine off?  It should not be, unless you are measuring the input (in effect a supply from the starter battery) to the relay that controls battery charging when driving.

You say no 12V supply to the fridge.  Again, that should only be live with the engine running.  So with the engine off, no 12V would be normal.

Some vans have a relay to isolate all 12V in the habitation area when the engine is running, except to fridge and leisure battery for charging.  I wonder if your van has such a relay?  If it has, and that relay has failed, or as Jon suggests is not being energised, it would have an effect similar to that which you describe.  So, when the supply from the alternator is confirmed, relays should switch to charge leisure battery, feed fridge, and isolate everything else except heating and step.

You say you have effectively by-passed the control relays and everything then works.  The problem, it therefore seems to me, lies in the 12V feed to those relays from D+, either directly, or indirectly via the main relay/s that controls battery charging and fridge feed.  (This may be a "split charge" type relay, or just two independent relays each taking their switching signal from D+.  One function connects the leisure battery to the alternator for charging, the other connects the fridge to the alternator.)  Your wiring diagram should illustrate the switching sequence of the relays, as well as what they feed.  (By that, I mean whether they all switch at once, or whether they cascade with each in turn only being energised as its predecessor switches.)

I do just wonder whether the dealer may have reversed the connections when he sorted your earlier problem, or swapped in a relay of insufficient capacity, or of the wrong type.  Automotive relays often have several terminals, and getting the feed to the wrong one can produce unexpected results.

My suggestion (with 230V mains disconnected) would be to find the end of the supply from D+ at your charge control relay (probably on/near the distribution board, but possibly sited elsewhere), and check you have volts there with the engine running (if you haven't, that wire is disconnected/cut somewhere), and none with the engine stopped.  Then, with the engine stopped and the D+ feed disconnected at the relay (just in case), bridge the feed and supply terminals at that relay (in effect by-passing it) and see if anything else now comes up live.  If it does, switch off all appliances/lights etc (to reduce drain on the starter battery), and then switch the fridge 12V supply on to check if it is getting 12V.  If that proves live, given that you verified the D+ supply is good, the relay has failed.  If that is behaving as normal, work you way down the various relays, checking each in similar fashion, until you find the one/s that have (I think) failed.  Hope this helps.

[Brambles]

Hi Again.

 

Thanks for links to cct. I understand the circuit. Following everything you have mentionened over all posts is the hard part. So as Brian as suggested a step back needed.

 

I would start by checking the D+ circuit. From the cct diagram you can identify D out. So with engine off and leisure reconnected, carefully check all D outs are zero volts. Then start the engine and check all D outs go to 13 volts. The important ones being from REL2B (on CT4 and CT5). This checks that relay is operating. To check Rel7B check battery voltage (no mains hook up). When you start the engine it should rise slightly. When you stop the engine fall slightly, then when you diconnect the battrey +ve it will fall to zero.

 

If you have Rel7b then there should be no other split charge relays fitted exterenally. If there is no REL7b fitted then you have an external split charge relay.

 

Once you have that checked and working we can move on what to test next.

 

[AL68]

The problem may be solved. I sent the new boards back to the supplier who had a donor to carry out a check. The control panel was fine BUT the power distribution board was faulty. I suspect as was suggested by Brambles that the processor was wrongly identifying low voltage supply. The manual states that if it falls below 10 Volts it will close down water pump and lights. I have heard of new components having faults, most recently from the technician at the dealer where I purchased the MH. A new working set is on the way.

 

A couple of things on my mind now. Why did my board develop the fault? it is not an uncommon failing as I understand (from various sources). Any thoughts on installation and commissioning?

 

Secondly, I am going to keep my "broken board" as an emergency spare. I discovered that there is a spare 12 volt connection which can be used to run the water pump. This connection is protected by an auxiliary fuse on the board. I am then thinking of bypassing the relay for the lighting with a soldered connection to the relay terminals (alternatively, rig a circuit to energise the relay). Power will still pass through the existing lighting fuses. I could put a switch in the circuit but not sure this is necessary as I could switch off the leisure battery (it has an isolation switch) and remove fuses if I need to work on the 12 volt lighting circuits (thinking of fitting LED's) The spare board would get me back home or to a dealer for repairs.

 

Thanks to all for help so far.

 

Alan

[Brian Kirby]

No answers to questions, but I hope the replacement works properly!  Can you re-jig the original so that the low voltage protection is removed from the circuit?  It would mean you risk running the leisure battery flat, but with careful monitoring, and knowing the possibility exists, it would at least enable you to finish a trip as planned.

[AL68]

This problem has rectified itself before the arrival and fitting of the new tried and tested board!!!!!! What have I done to help it? Apart from poking here and there, plugging and unplugging etc., nothing. I took it on a 50 mile round trip 5 days ago after which it was still not working. Another round trip of 10 miles yesterday after which I noticed it had come back to life. The battery condition may have improved a little I suppose. Perhaps there is a poor connection, dry joint, faulty component. Trying to locate a fault in a working system is going to be harder than ever.

[Brambles]

The most common fault on PCB assemblies are dry joints and this certainly could be what is wrong. Not so hard to find, if you take the PCB out and inspect with a strong magnifier and bright light. Any, and I mean any suspect joint should be resoldered. Look for larger components with thick wire leads or spades soldered on the PCB, and large resistors. Failure of electronic compoments operating with in their specifications very rarely fail these days. I did an excercise once of testing all the components a repair technician had replaced on new products under test over a period of a month. Not one component was faulty, meaning what he had repaired was a dry joint, or possibly a sliver of solder shorting legs.

On some products where he failed to trace a fault a common technique was to coat with flux and repass through the soldering reflow machines. Invariably worked.