Fridge fault

My Thetford fridge works OK on mains and gas but displays ‘fault code 6’ when trying to run on 12v. This I understand means the 12v supply is ‘out of limits’. My split charge relay appears to work normally and the fridge fuses (behind drivers seat) are good. Believe there is an additional fuse behind the fridge which may be accessed through the lower external vent but I have been unable to discover the special magic required to remove the vent .... any helpful suggestions would be gratefully received. Should this fuse be ok then I guess it’s a fridge removal job to check voltages present at the terminals. Thanks in anticipation. Peter M

The external fridge vents are held in place by sliding lugs that you should be able to see towards either end of the vent from outside the van, these are easily slid across with a screwdriver

The vent grills are indeed held in with two clips at top l/h and r/h which you slide across to release[You must be registered and logged in to see this link.]

Thank you so much Bilbo and Kdc .... will give it a go.
Peter M

The fuse you should find at floor level spliced into wiring harness.

Peter,

I’ve not experienced that fault but I have had to access the rear of our Thetford N3000-series fridge in order to replace the 240V heating element and can offer some pointers.

Your Warwick is similar in age to our Kemerton so our Thetford fridges are most likely in the same series if not the identical model. I was able to gain full access to the electrical system of the fridge from outside the van, via the lower vent aperture, and can confirm there is no 12V fuse behind the fridge. There is a glass fuse on the power board, though I can see no reference to this fuse in Thetford’s fault finding tree for a Code 6 fault, so I doubt if this is the issue.

I would focus instead on the EM50, which is a Sargent box that provides the interface between vehicle and habitation electrics. It contains fuses and relays and routes the 12V supply to the fridge for operation while underway. There is a separate 12V supply (low current) from the habitation side to power the fridge display, but from what you’re said it sounds like the high current 12V from the vehicle alternator that is in question. AS often site their the EM50 in a difficult-to-access location near the cab; ours is behind the driver’s seat. The picture below shows the fuse and relay details so you could start by checking Fuse 7.

Let us know how you get on.

Tim

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Thanks Tim, I have removed, checked and replaced all the fuses and can confirm they are all in the fuse holders correctly and there is no sign of corrosion or overheating. When engine is started the habitation electrics ‘click’ off and the step retracts so believe the split-charge relay is operating correctly. Also, a nice charge is being fed to the leisure battery (13.9V)
So, logic would seem to suggest the problem lies either with the fridge itself or the ‘high current supply’ from the split charge relay. Should be able to determine which, when I can gain access to fridge electrical connections.
The Sargent interface is indeed in a most difficult place to access !
Peter M

Kdc wrote:The fuse you should find at floor level spliced into wiring harness.

To correct myself….the fuse I mention is spliced into my supply line to feed cooling fan not the fridge.

Peter,

In that case the next point is to confirm whether you have a 12V feed at the power board terminals in the rear of the fridge, while the engine is running. I’ve attached a picture of the fridge electrics, viewed through the lower vent aperture and with the power cover removed. At the time I was only interested in the cables to the 12V and 240V elements, which are the black and blue pairs on the right of the picture. I don’t know which cable carries the high current 12V feed but on the basis of thickness would guess it’s the red and white next to the blue pair. You’ll be able to remove the connector from the board by prising open the plastic locking latch and pulling downwards. It may also be secured by a cable tie which appears in the picture.

Check with your meter across the terminals without the engine running (should be 0V) and with the engine (12V). If you get this result then I think it points to a faulty power board, but you may get further advice from Thetford’s tech help, who helped me with my fault. If you don’t get this result then either I’ve guessed the wrong cable or there’s a cable fault (unlikely I feel). It’s possible that the connector onto the board has worked loose but I found them to be well fitted. It’s possible that a connector has worked loose on the EM50 but I have no knowledge of how that unit is engineered.

If you conclude that the fridge power board is faulty (and it’s not uncommon for them to fail) then it’s not too difficult to replace it yourself. I’ve had ours out and although a fiddle, it was achievable. I now carry a spare board in the knowledge that I could replace it if it failed while on tour. I can talk you through it if and when you get to that point in your diagnosis.

Ignore my arrows on the picture, which were added to explain how I replaced the 240V element.

Tim



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behind the drivers seat (floor level) EM40, have you removed it and checked the fridge supply wiring socket underneath ?
ours had burnt out from incorrect crimping and loose fit.
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soldered a new wiring block on ours with new connectors, a little bit of a tight squeeze to get in there but it can be done.
Have spare new black multi plug and connectors if you need one, from Sargent.
PS where and what ever that black plug supplies, it sorted our 12V fridge issue out while driving.
Hope this might help and board is attached to floor with four small black screws if you did not know.

I hope I never face that problem Babian, our EM unit is even trickier to access. I think I’d need to remove either the driver’s seat or the end panel of the bench seat. 

Was there adequate play in the cable loom to pull through and re-engineer the connectors?  It’s bad enough that they site these user-serviceable units in such out-of-the-way places (presumably because it minimises any extension to the vehicle cabling) but to then compound it and make up the connectors ineffectively is really poor.

Tim

Hi Peter, if you have 12v at the fridge with the engine running,I recommend you check the 12v element hasnt burnt out.I had this on a previous van.Mobile electrician found it straight away when it with his circuit tester.Replacement was£49 he ordered and fitted it for£100.

KB, yes there was a little bit of play in the wires (lots of wires to be seen)
easiest option was to turn the EM40 over 90 degs , make a note of plug positions or take a phone photo and pull them all off the back of the board. Cordless soldering iron comes in handy.

I like asking my close family for useful birthday and Christmas presents.
Cordless soldering iron 
chamois leathers
obscure shed tools
12V motorcycle gel battery was latest
All useful and wanted by me but always get the reply   "is that all ? "

Thanks for all your most helpful suggestions .... too wet n orrible to make further progress today. I think checking the EM40 connections would be a good next step as I had to disturb that area whilst replacing ‘those’ blue led’s with warm white ones. Peter M

babian wrote:KB, yes there was a little bit of play in the wires (lots of wires to be seen)
easiest option was to turn the EM40 over 90 degs , make a note of plug positions or take a phone photo and pull them all off the back of the board. Cordless soldering iron comes in handy.

I like asking my close family for useful birthday and Christmas presents.
Cordless soldering iron 
chamois leathers
obscure shed tools
12V motorcycle gel battery was latest
All useful and wanted by me but always get the reply   "is that all ? "

Thanks Babian!

Had a good long session at tackling ‘the issue’ today and ‘fingers crossed’ it is sussed.
First I checked the 12v supply behind fridge (via lower vent cover) and measured 12.6V with my DVM. As an additional check I connected a 50W bulb to the supply cable and it only glowed dimly ie there was some resistance in line.
So, back to the EM40 and waggling the fridge plug caused the bulb to go on/off and all states in between. There were no signs of corrosion or overheating, just a poor contact ! Manipulated the ‘springy’ parts of the spade connector which now makes good contact. Also removed the pub (4small, easily lost screws) to check the solder joints and all were good.
Hoping it will now get us through this years cruising season and perhaps I’ll look for a better solution next Winter.
I really appreciate all your helpful advice.
Peter M[You must be registered and logged in to see this link.]

Aahhhh .... delete ‘pub’ and insert ‘pcb’

Good diagnostic process, pleased to know you fixed it. These vans are a continual learning exercise!

Tim

Good to know you have fixed it Peter M. Like Tim wish the EM50 on the Kemerton was as easy to access as the EM40 in the pic. The fridge plug on my EM50 was burnt out some time ago, caused by a loose earth connection at the E battery [discussed some time ago on this forum]. Now resigned to having the EM50 unit replaced when I have found the correct model number. After discussing the issue at length with Sargent, they said:


‘Unfortunately the EM 50’s cannot be repaired and your only option is to purchase a new one. There should be a sticker on your EM50 which should confirm what type you need. I believe for an Autosleeper it will be an EM50 type C but please verify this inspecting the sticker on the circuit board’.
Its not been a major problem running the vehicle without the fridge being switched onto battery power, but now, coming out of lock-down it will be useful to keep food etc cool. Next step  find the model number. Find someone competent to remove and replace the unit.

Any one know where the em40 is on a Warwick duo fridge 12v failed on way to rally

Behind driver's seat, black box on end wall of kitchen.

Not on my van Paul struggling to find it

If it's the same as our 2018 duo it's at the back of the van (rhs) under the seats.
Em40 panel with the 12 volt connection is on top Ec40 unit.
We recently had a similar issue.
Good luck

Cheers suf wait til we get back now