RM7401 / EBL 269 problem

[Pilote87]

Hi Gals and Guys,

I have a problem with the non functioning of my fridge. I have removed the cooker hob so I can access the top of the fridge and have checked the voltage at the 12 volt terminals. Strangely, I am seeing different voltages depending on which energy function I select, but they are all below 6.2 volts. I haven't, as yet, checked the voltages with the engine running. On the overhead panel I have a reading of over 13 volts, believable because the sun is still on the solar panel. The engine battery is showing 12.7 volts, although probably irrelevant.

Any ideas, please?

 

[1967bowesj]

Hi Gals and Guys,

I have a problem with the non functioning of my fridge. I have removed the cooker hob so I can access the top of the fridge and have checked the voltage at the 12 volt terminals. Strangely, I am seeing different voltages depending on which energy function I select, but they are all below 6.2 volts. I haven't, as yet, checked the voltages with the engine running. On the overhead panel I have a reading of over 13 volts, believable because the sun is still on the solar panel. The engine battery is showing 12.7 volts, although probably irrelevant.

Any ideas, please?

What’s wrong with the fridge?

 

[Pilote87]

What’s wrong with the fridge?

It doesn't operate on any of the energy sources. The light which indicates the fuel selected is very dim in all three positions - not surprising if there is only half the required voltage.

J

 

[GeoffnDee]

have you checked the power module 12v supply ground connection.(I believe that the burner control and gas valve operate at 1.5 v via the power module)
If you need it , there is an operation manual (including a wiring diagram) for The Dometic 7 series fridge on page 4 of Manuals for Motorhome Stuff that is in Resources (found in the menu)

 

[1967bowesj]

It doesn't operate on any of the energy sources. The light which indicates the fuel selected is very dim in all three positions - not surprising if there is only half the required voltage.

J

Check all the connections on the top of the fridge and down behind, take bottom external cover off. Possible causes are corroded terminals so split any push fits and clean then up. There’s 2 12v feeds to the fridge, high and low current. Sounds like low current if all are not working and panel dim.
As GeoffnDee said, check ground connections!

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[Pilote87]

Thank you GeoffnDee for the suggestions. Although it is very sunny here, the temperature is at or about zero, so I'll wait a while before carrying out further checks.

1967bowesj, Thank you. I have the manual in French. The fault finding guide isn't much use, hence my query on here, but having the English version removes any doubt from my limited translation skills. Again, I'll wait for the temperature to rise a little.

John

 

[1967bowesj]

Thank you GeoffnDee for the suggestions. Although it is very sunny here, the temperature is at or about zero, so I'll wait a while before carrying out further checks.

1967bowesj, Thank you. I have the manual in French. The fault finding guide isn't much use, hence my query on here, but having the English version removes any doubt from my limited translation skills. Again, I'll wait for the temperature to rise a little.

John

Yeah, just been in our van for my spare glasses, minus 4, I’ll leave them a while to warm up

 

[Pilote87]

Yeah, just been in our van for my spare glasses, minus 4, I’ll leave them a while to warm up

Well, I've braved the cold wind blowing straight from England (it should have warmed up a little after a 500 mile journey) and have checked the voltages at the 12v dc terminals. With the fridge turned to "off" I have 12.48 volts, when turned to any of the three "on" positions I have around the 6 volts level. I've disconnected the fridge (purple and black wires) from the 12v terminals and the reading is back to 12.48 volts. I have separated and re-made the earth connections on the top of the fridge as well as those I can see through the external access.

Am I correct in thinking that the control unit that GeoffnDee referred to is the unit which sits behind the fascia)? That is where all the wiring leads to. If so, I will have to pull the fridge forward in order to access the screws for the cover of that unit as I don't have a shallow right-angled cross-point screwdriver. Right now, I'll remove the fridge shelves and look for the screws going through into the side panelling.

As an aside, I'm also looking at removing my Traumatic C4002 which has failed. Two dealerships and a repair workshop have told me it is no longer repairable. The repair workshop suggests around 4000€ to supply and fit a Combi 4 Inet X, with all the necessary pipework and ducting required.

Right, back to the cold to do more checking.

Thanks,

John

 

[GeoffnDee]

I think that if you remove the control knobs there are screws behind them that secure the fascia.

 

[Pilote87]

I think that if you remove the control knobs there are screws behind them that secure the fascia.

Thank you. I'll have a look in the morning, once the sun has warmed us up a little.,

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[Pilote87]

Well, I didn't get far with that, GeoffnDee. I did try removing the knobs on the front panel, but they seem to be recessed into the forming of the panel and it isn't possible to get any grip on them. After disconnecting the gas supply I also tried easing the fridge out of its housing, but it will only move about a centimetre.

Later this morning, after I had done some more probing, I needed to go on line. The internet kept dropping out. Eventually, I ended up taking my fibre link box which gives me WiFi signals around the house, including for my TV, back to the shop to exchange for one which works.

I'll try some more things tomorrow.

 

[GeoffnDee]

According to the Dometic 7 series service manual the knobs pull off from the electronics control module that is behind the fascia , if the retaining screws are not there try looking under the base of the fascia for them (the knobs need removing either way)
www.leisurespares.co.uk have parts diagrams for these RM7401 fridges , showing the knobs and fascia etc , which may help .

 

[Pilote87]

Sorry, I had gone to bed before your reply came. Earlier this morning I used some mole grips with protected jaws to grip the control knobs and - Hey Presto - the two screws behind the control knobs, three screws along the top of the control unit, plus the screw on the cable clamp and I'm in.

I'm guessing that there isn't a diagram showing test points with expected voltages for the pcb within the enclosure. I think I'll pose the same question to Dometic and see what they say.

Thank you for your good guidance.

John

 

[GeoffnDee]

I cannot help with expected voltages (except for the 1.5v at the gas valve and burner control ) but If you need the pcb tested/repaired have a look at www.qualityelectronicrepairs.co.uk

 

[Pilote87]

I If you need the pcb tested/repaired have a look at www.qualityelectronicrepairs.co.uk

Thanks for the link. However (there is so often a "but" or "however") I have been braving the cold, no wind today, and, just inside the top vent grill there is a strip of connectors for 12 volt direct, I think 12 volt D+ and a third pair I haven't explored. Now I'm only getting 7+ volts on the supply side, whereas I was seeing well over 12 volts on Sunday. The battery is definitely well charged, according to the overhead panel. I'll have another look tomorrow afternoon and run a temporary supply direct from the battery to the fridge terminals.

I've had a look at the EBL booklet and it suggests that the fridge supply should be run direct from the battery. There is a 20A fuse in the EBL, but is designated for the AES fridge, whereas mine is the MES version

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[Pilote87]

Hi GeoffnDee and 1967bowesj . Having run a cable direct from the battery to the fridge terminals I now know that all the work in and around the fridge was in vain. I have the fridge working via the temporary cable. I didn't remember there was a fuse(10A) within the battery box for the fridge supply, but I know now.

In order to trace the original cable I'm going to have to get down and dirty, squirming underneath. That is, unless someone can tell me if it does go via the EBL. I can't find anything in the documentation.

 

[GeoffnDee]

Block 1 on the EBL appears to be linked to fridge operation and may be worth checking.

 

[Pilote87]

Block 1 on the EBL appears to be linked to fridge operation and may be worth checking.

After doing a few domestic chores, I had just picked up the EBL book to look. Thank you. I'll focus on Block 1

 

[GeoffnDee]

Block 2 and the fuses linked to it could also be worth checking.