Dometic 3 way fridge issue

[TONCAZ]

Fridge works fine on gas and 240v.
When I turn switch to batt position Red light comes on.
Checked fridge fuse on E box all ok is there another low voltage fuse anywhere, looked behind grill outside can't see one, any ideas

Cheers

 

[Mou and Iryna]

Mou and Iryna ,If you cannot find the 20 amp fridge 12v heater element fuse near the starter battery positive terminal there may be a separate Schaudt PLT02 relay/fuse module close to your EBL unit which contains this fuse.

Thank you Geoff. Much appreciate it

 

[Ianto]

No but I wrote to Thetford asking about an upgraded pcb and despite just being out of warranty they sent me a new one FOC. Great service but maybe they were concerned it would go on fire. They really should have recalled them all if it's such a problem.

have you got the part number for the upgraded pcb board. As I bought one part number 692247. However this didnt sort my problem. Cheers

 

[IRHP]

have you got the part number for the upgraded pcb board. As I bought one part number 692247. However this didnt sort my problem. Cheers

This is the new one.

 

[Ianto]

Yes same sort number but its the 6 figure number which is the part number. They changed the original to 692247 on mine. But still waiting for replacement. Cheers

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[DerryW]

I have a Thetforde 3 way fridge which had the same problem. Not sure how similar the Dometic is. There is a 20 amp fuse on the fridge PCB. I started at the plug behind the bottom fridge vent. There are 2 x12v feeds. One low current to operate the fridge (if fridge panel and lights are working this is ok) and one high current to provide 12V power when the engine is running (thicker red and white wires) and one signal wire ( D+) that comes from the alternator when the engine is running. This wire only has 12v positive when the engine is running. All these voltages checked out OK but the fridge still gave error code 6 which is 12v supply outwith limits of 10v -15.5 v. I removed the PCB cover ( one single torx screw) There's a 20 amp fuse that isn't visible until you remove the whole assembly from the mounting. Its held on by 2 bolts either side. Once they are off the pcb unit can be angled down to reveal the back of the pcb. I could see some scorch marks on the rear of the pcb so decided to get to the fuse on the other side. There's 3 screws on the pcb but only one that needs to be removed to release the board. The 12v power feed plugs have to be removed to release the board so that you can see the other side where the fuse is mounted. It was pretty obvious this had blown. I replaced it put it all back together and it's now working fine. I'm a bit sceptical that it might happen again as it takes quite a bit to blow a 20 amp fuse. I'll see how it goes

RIHP

I appreciate this thread is almost a year old, but I too have exactly the same problem. I checked both 20a fuses at the PSU and the battery terminal, both okay, so I took off the black cover that hides the PCB, and as you've described 2 terminals looked scorched. We're away at the moment down in sunny Cornwall so a job that will have to wait until we're home next week.

One thing I noticed after removing the black cover (single T20 screw) was the poor design for catching the water from the freezer overflow. It drains from the overflow pipe into a small white plastic container which sits directly above the condenser, where I assume the water evaporates over time. that's all well and good, but, if as mine was about to do "overflow" it drips straight onto the 240v and 12v connectors. I cut a small corner off of a sponge and used that to empty the plastic container.

I cant make out why Adria didn't simply use a longer piece of pipe and run it to the large hole in the floor right beside the grille.

I'll add some photos when I get home which will hopefully explain better than I have just tried. This might be useful to others experiencing the same issues.

Thanks Derry

 

[IRHP]

RIHP

I appreciate this thread is almost a year old, but I too have exactly the same problem. I checked both 20a fuses at the PSU and the battery terminal, both okay, so I took off the black cover that hides the PCB, and as you've described 2 terminals looked scorched. We're away at the moment down in sunny Cornwall so a job that will have to wait until we're home next week.

One thing I noticed after removing the black cover (single T20 screw) was the poor design for catching the water from the freezer overflow. It drains from the overflow pipe into a small white plastic container which sits directly above the condenser, where I assume the water evaporates over time. that's all well and good, but, if as mine was about to do "overflow" it drips straight onto the 240v and 12v connectors. I cut a small corner off of a sponge and used that to empty the plastic container.

I cant make out why Adria didn't simply use a longer piece of pipe and run it to the large hole in the floor right beside the grille.

I'll add some photos when I get home which will hopefully explain better than I have just tried. This might be useful to others experiencing the same issues.

Thanks Derry

I know exactly what you mean and it's what I've done, just extended the tube down the hole after asking Thetford if the evaporator is there for a reason, they said it would be fine.

 

[IRHP]

RIHP

I appreciate this thread is almost a year old, but I too have exactly the same problem. I checked both 20a fuses at the PSU and the battery terminal, both okay, so I took off the black cover that hides the PCB, and as you've described 2 terminals looked scorched. We're away at the moment down in sunny Cornwall so a job that will have to wait until we're home next week.

One thing I noticed after removing the black cover (single T20 screw) was the poor design for catching the water from the freezer overflow. It drains from the overflow pipe into a small white plastic container which sits directly above the condenser, where I assume the water evaporates over time. that's all well and good, but, if as mine was about to do "overflow" it drips straight onto the 240v and 12v connectors. I cut a small corner off of a sponge and used that to empty the plastic container.

I cant make out why Adria didn't simply use a longer piece of pipe and run it to the large hole in the floor right beside the grille.

I'll add some photos when I get home which will hopefully explain better than I have just tried. This might be useful to others experiencing the same issues.

Thanks Derry

There is a 3 year warranty on Thetford Fridges but they replaced my PCB FOC despite just being outwith the warranty.

 

[Ianto]

I have had the same issue. Finally got it sorted after receiving a faulty pcb. They replaced and thankfully it all working.

 

[DerryW]

Following up on #35. I finally got around to removing the PCB and, as thought, the 20a fuse had blown, replaced with new and all operating fine.

As you can see I numbered all the terminals to aid refitting, but in truth you only need to remove 2 cables and disconnect the 2 large connectors(12v & 240) and you can pull the PCB out far enough to get to the single screw which allows removal of the PCB and access to the fuse.