Dometic 3 way fridge issue

Joined
Dec 30, 2019
Posts
402
Likes collected
347
Location
Manchester, UK
Funster No
67,710
MH
Burstner t700
Exp
Early 2019
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
 
The Dometic fridge is designed to work on 12v when the engine is running. You don’t state whether it is or isn’t . If it doesn’t work when the engine is running,it’s almost certainly a fuse.
 
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The Dometic fridge is designed to work on 12v when the engine is running. You don’t state whether it is or isn’t . If it doesn’t work when the engine is running,it’s almost certainly a fuse.
Sorry parked and running still the same
 
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Take the cover off the outside and check with a meter that the element is getting power when engine is running.
If not then poss relay or fuse problem backwards from there, or if it is then knackered 12v element even.
 
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We had the same symptoms on our Fiat based Burstner Solano t725 after we had a duff starter battery replaced at a Norauto depot in Spain.

After much head scratching, I discovered that the 20amp fuse attached to a lead connecting to the positive terminal of the new starter battery was missing and I found it down the side of the battery box.

I replaced the fuse and fridge started working again on 12V when engine was running.

Good Luck.

IMG_20180328_190248.jpg

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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 😀
 

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We had the same symptoms on our Fiat based Burstner Solano t725 after we had a duff starter battery replaced at a Norauto depot in Spain.

After much head scratching, I discovered that the 20amp fuse attached to a lead connecting to the positive terminal of the new starter battery was missing and I found it down the side of the battery box.

I replaced the fuse and fridge started working again on 12V when engine was running.

Good Luck.

View attachment 703016
Cheers will make that 1st point of call..
 
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Is this button to the rear of the fridge? don't remember seeing it on the front
Ours is on the front on the rail between fridge and freezer😊 the one on the right
A7F639B4-510E-4939-9DCB-A7D1F4783E4A.png
 
Last edited:
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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. It’s 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 😀
Same problem with my Dethleffs. Did you have any repeat of the fault after you changed the fuse?
 
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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.
Same problem with my Dethleffs. Did you have any repeat of the fault after
 
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Cheers will make that 1st point of call..
Hello there. I have a Dometic fridge which works well on gas and 220v but not on 12v. I have a Burstner 726 on a fiat ducato chassis and engine. Do you think it is the fuse? If so, where is it located?. Thank you
 
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Hello there. I have a Dometic fridge which works well on gas and 220v but not on 12v. I have a Burstner 726 on a fiat ducato chassis and engine. Do you think it is the fuse? If so, where is it located?. Thank you
Mine is next to the starter battery between the two front seats (on a Renault master) 20amp yellow
 
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Mine is next to the starter battery between the two front seats (on a Renault master) 20amp yellow
Thank you. Will check it out. Reading through here, it seems to be either the relay or the fuse. Will check out. Cheers 👍
 
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