3 way fridge not working on 12v (1 Viewer)

[Helen Ariel]

Help please. As we've just run out of gas our fridge has stopping running and we have just set off to drive for an hour to get gas thinking the 12v would kick in on the drive but the fridge is still flashing that it's not working. I even switched from auto setting to manually put it on 12v but it's still flashing. Engine running, batteries have plenty of charge. Any ideas? It's a thetford and is a year old.

 

[XxAnthxX]

Fuse in the d+ (engine running) feed to the fridge. Check the fuses in the fuse box again.

 

[Helen Ariel]

Fuse in the d+ (engine running) feed to the fridge. Check the fuses in the fuse box again.

Sorry can you elaborate on the d+ thing?

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[Landy Andy]

Have you turned it off then on again, as it may be just confused as you ran it out of gas, before switching across.

 

[XxAnthxX]

The fridge will have two 12v power feeds.....the main supply and a smaller cable (d+) which is a 12v signal so the fridge will operate only with the engine running, check the fuse for this feed.

It could be shown on the fuse box as two squares joined together.....mine is like the three amp one on the right as it also supplies the simulated engine running signal to my split charge relay, hence looking like two battteries linked)

Yours could be different or inline somewhere.

 

[Helen Ariel]

Have you turned it off then on again, as it may be just confused as you ran it out of gas, before switching across.

Yes tried that.

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[Helen Ariel]

The fridge will have two 12v power feeds.....the main supply and a smaller cable (d+) which is a 12v signal so the fridge will operate only with the engine running, check the fuse for this feed.

It could be shown on the fuse box as two squares joined together.....mine is like the three amp one on the right.
View attachment 445974

Yours could be different or inline somewhere.

Thanks we'll have a look at the fuse box when we get to Lagos. Clueless newbies here.

 

[XxAnthxX]

Clueless newbies here.

We all learn something new with each fault we have....

 

[The Old Man]

When my fridge stopped working on 12v, but good on the other two sources, a small cable from the battery to the electrobloc had failed, that in itself stopped the fridge working but the short caused a failure in the electrobloc so that needed some refurbishment.

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[namwaldog]

We had the starter battery replaced in Spain a couple of years ago. When we left the workshop, the fridge wouldn't work on 12v whist driving.

Eventually worked out that there was a 20A fuse on the +ve terminal of the starter battery and the fitter had dislodged it. Refitted fuse, problem fixed.

Burstner based on a 2010 Fiat Ducato. Starter battery under floor by passenger footwell RHD.

Good Luck

 

[Helen Ariel]

Best pic I can get. Model is the Schaudt Elektroblock EBL102.

 

[Lenny HB]

Sent you some info in a PM Helen & my phone No.

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[The Old Man]

Sent you some info in a PM Helen & my phone No.

You have to love Funsters.

 

[BuilderBob]

I think the electric element is a prime suspect, they are a very common failiure in a domestic setting

A test meter across the element terminals will confirm, closed circuit ok, open circuit, element failed, quick and easy without dismantling anything.

 

[autorouter]

On the EBL102, the fuse for the 12V power to the fridge 12V element is not quite in the picture. There are two fuses just to the left. If it helps, 'Internes Lademodul' is the Internal Charger Module, and 'Kuhlschrank' is the Fridge. It's a 20A fuse.

There is another 20A fuse, as namwaldog says, near the starter battery. There's a main fuse, probably 50A, and next to it is the 20A fuse. There may also be a third fuse, 2A, in that location.

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[Dave Scadding]

Hi, had similar issue all fuses ok from engine compartment back to fridge relay behind external vent area. Also fuses in domestic fuse / MCB consumer unit. Turned out to be changeover relay in engine compartment not sending power when required.

 

[pappajohn]

An hours drive to get more gas is neither here nor there.... The fridge will stay cold far longer than that if the door isn't opened.
Sort the 12v later when you have gas again.

 

[Helen Ariel]

An hours drive to get more gas is neither here nor there.... The fridge will stay cold far longer than that if the door isn't opened.

Yes but we need to get it working again for when we do do longer trips. Just discovered it wasn't working because we ran out of gas and had expected the 12v to take over on the drive.

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[Helen Ariel]

It hasn't stopped raining or blowing a gale since speaking to Lenny HB on the phone so we are yet to get the multimeter on the circuit to check resistance. Hopefully tomorrow. All fuses removed and checked seem fine.

 

[autorouter]

When you get round to checking behind the fridge, it helps to know that there are two separate 12V supplies, and in addition there's the D+ signal.

The 'low power' 12V supply comes from the leisure battery, and runs the fridge control board. It's more or less permanently on, even if you switch the 12V habitation off on the display panel. It must be working OK, because the gas and mains wouldn't work without it.

The 'high power' 12V supply comes from the starter battery/alternator, and only feeds the 12V fridge heater element. There's a 20A fuse on the EBL and a 20A fuse near the starter battery, as described previously.

The D+ signal is a wire from the alternator that is 0V when the engine is stopped, and jumps to +12V when the engine has finished the startup procedure and the alternator is running properly. It is used generally as a signal that the engine is running. The D+ signal goes to the EBL, and switches various relays like the split charge relay and the supply for the 12V element of the fridge. Also, it goes to the fridge control board, and is used by the Automatic Energy Selector (AES) to decide what power source to use (mains, gas, 12V).

So you can see that there are lots of places where it could go wrong.

 

[mitzimad]

I think the electric element is a prime suspect, they are a very common failiure in a domestic setting

A test meter across the element terminals will confirm, closed circuit ok, open circuit, element failed, quick and easy without dismantling anything.

you need to diss one terminal or you could get a circuit back to the electrobloc

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[Helen Ariel]

Will get some pictures tomorrow when we attempt this. Thanks all.

 

[PG’s trips]

Hi Helen, had similar problems on my 4year Thetford fridge. Had to replace the control panel on the fridge itself after exhausting all the fuse issues. Fairly easy to replace and get one...though about £100

 

[Helen Ariel]

Ok, here’s the pics from the back of the fridge;

Engine running gives 14.38v

Engine off gives 13.28v, not sure why pic is upside down!

Split the connector with the 12v feed and it measures 1 on the 2000 scale of resistance.

Cover off but I can’t work out which is the D+ feed as the only wiring diagram I can find is a bit vague...

Thanks for the help so far!

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[Helen Ariel]

On the EBL102, the fuse for the 12V power to the fridge 12V element is not quite in the picture. There are two fuses just to the left. If it helps, 'Internes Lademodul' is the Internal Charger Module, and 'Kuhlschrank' is the Fridge. It's a 20A fuse.

There is another 20A fuse, as namwaldog says, near the starter battery. There's a main fuse, probably 50A, and next to it is the 20A fuse. There may also be a third fuse, 2A, in that location.

Ok, found the other two fuses. Both seem ok.

Also found a 40a, 10a and 2a by the leisure batteries under the drivers seat. If you pull the 2a it switches the whole 12v system off so it’s fine.

Will check for the starter battery by the passenger seat as mentioned by namwaldog

Cheers!

 

[pappajohn]

Don't rely on visual inspection of fuses, they can blow where it can't be seen.
Always use a meter set to OHMs.

 

[autorouter]

The low-power supply is the violet (pos) and black (neg) thin wires on that connector you were probing. It should be on all the time.

I can't find a definite diagram showing the D+, but by elimination it's most likely to be the orange wire. You could try that (probe between orange D+ and the black negative wire) with the engine running/stopped to see if it changes.

The 1 ohm reading looks OK to me. It's not very accurate (more than 0.5 but less than 1.5) but if there was a fault it would read 0 or OVLD (very high resistance). For slightly better accuracy you could try on the 200 range. Before you measure, touch the probes together to measure the probe lead resistance, and subtract it from the element reading. I'd expect about 1.4 for a 100 watt element, 0.7 for a 200 watt element.

For example, if touching the probes shows 0.3 ohms, and the element reading is 1.0 ohms, then the true element resistance is 0.7 ohms.

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[Fat ale]

Have you checked the EARTH on the fridge itself ?

 

[Plumb]

Morning I am fairly sure the D+ wire is the orange wire ,if you search Thetford AES fridge wiring diagram you will find Thetford fridge installation drop down menu where you can choose your particular appliance , it will include the appropriate wiring diagram which hopefully will help ! Good Luck

 

[Wikky]

Have you turned it off then on again, as it may be just confused as you ran it out of gas, before switching across.

I have to turn mine off and on again to get it to work on another energy source.

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