Help please with Dometic fridge (1 Viewer)

Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
Hi,
I have a Dometic fridge model no. RM7655L
The fridge is not working on 230v or gas. Gas not sparking.

The fridge is receiving power both 12v and 230v and the AES knob is working but the temperature knob is only showing the lowest setting.

I believed the temp spindle may be broken so I stripped the top control unit down on fridge but it was intact.

Looking for advice please?
 

glenn2926

Free Member
Sep 11, 2012
3,326
13,619
Gods country
Funster No
22,848
MH
Chausson
Exp
newbie hired 3
Is your van level? It needs to be fairly level to work. Mine didn’t work one time. I turned it round on the drive and it started work straight away.

Subscribers  do not see these advertisements

 
Jul 12, 2013
3,869
5,262
The City of Henlow
Funster No
26,906
MH
Adria Supreme
Exp
Since 1980
I am not trying to be funny but read the handbook carefully. Unless a real odd ball problem they can be informative. I speak as one who only under extreme duress would I look into the Manual.
Not being level is good advice. Of the three forms of cooling, the electrical is the sure fire clue to problems. If it works, you are onto a good start as gas can be affected by many more failure possibilities and 12v really needs the engine running and then only supplies support power.
 

bigtwin

LIFE MEMBER
Oct 29, 2009
5,241
9,942
Derby
Funster No
9,111
MH
Concorde
Exp
Since 2006
Given the symptoms being described (no sparks from the gas igniter), it’s unlikely that it’s a levelling issue.

Ian
 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
Thanks for advice. Van is level. Due to the fact that van has a power supply and not sparking on gas I am a bit stumped. I cannot identify any fuses blown. I have checked all connections and tightened screws.
I have checked manual but limited information.
Thinking it may be the burner control as no spark?

Subscribers  do not see these advertisements

 
Sep 6, 2019
185
243
Newcastle Upon Tyne
Funster No
63,854
MH
Autotrail Frontier
Exp
since 2015
Hi Toady
I believe this model fridge has auto setting,Is it neither working on 'auto' or manual select.
I had a problem with my fridge last week,wouldn't work on 240v,would light on gas but only run for 10 mins or so.
Switched everything off & unplugged mains cable, removed the fuses from the battery supply in the sargent unit,this can re-set the fridge. left like this for 5mins.
Put the fuses back, started the van up & ran engine for a few mins. after this it worked fine again on both gas & 240v.
It worked for me & worth a try.
Kev
 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
Hi Kev,
The fridge is not working on auto or manual. I have previously reset it but with no success. I will try a full reset as you suggest (fingers crossed) and let you know later today.
Cheers
Toady
 

sallylillian

LIFE MEMBER
Oct 29, 2011
3,944
5,014
Falmouth, Cornwall
Funster No
18,670
MH
Palace Liner 90LO
Exp
2011
Have you put a meter across the 2 off 12vdc connections and the 230vac connections at the back under the metal cover? There are 2 12vdc feeds heavy cables and thin ones. The heavy ones feed the 12vdc heater the other thin ones are obligatory for the system controls.
 
Apr 6, 2019
3,737
7,445
Eye, Peterborough, UK
Funster No
59,702
MH
RV
Exp
FourWinds Windsport 6.8L V10
12V feed wires
If you have a switch to press to activate the "spark click" these are cheap as chips and can fail
 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
Thanks again for the advice everyone. I now in my ‘scruffs’ and on the motorhome. I will follow the advice given and report back shortly. Thanks

Subscribers  do not see these advertisements

 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
I have attached a couple of pictures of my fridge for assistance.
Things done so far:
1.Checked receiving 230V and it was
2.Checked with multimeter 12V heating element (Thick cables) and 12V electronic (Thin cables) and both receiving voltage 14V on multimeter
3. Took fridge fuse out of blue control box
4. Disconnected 230V and 12V to fridge to reset fridge.
After reset, started engine and ran fridge on 12V. It appeared to cool
Note: The thing I cannot get my head around is that when the fridge originally went faulty it was when the temperature gauge (right hand knob on control) stopped functioning. It is only showing one light bar as if in lowest setting. When this gauge stopped working was the same time the gas igniter (burner control) stopped working too. I have stripped the control unit down thinking the temp. gauge spindle was broken but this was not the case (refer to yellow spindle in photo)

I have now turned engine off and placed on hook up to see if it will work.

Views much appreciated please?
 

Attachments

  • C01B84A3-05C7-428A-8BA4-6CB9CCF8B605.jpeg
    C01B84A3-05C7-428A-8BA4-6CB9CCF8B605.jpeg
    140.2 KB · Views: 81
  • B51A0F11-B511-4EDF-B73B-30EA616361D0.jpeg
    B51A0F11-B511-4EDF-B73B-30EA616361D0.jpeg
    202.3 KB · Views: 82
  • 50CA38E7-E891-4492-94F6-4505EF31E506.jpeg
    50CA38E7-E891-4492-94F6-4505EF31E506.jpeg
    88.9 KB · Views: 83

willsd

Free Member
Aug 10, 2018
16
7
Funster No
55,516
In your photo it seems like it is set to gas. Also the temp control is set very low.

I suggest that you set the left hand control clockwise to AES. Then set the right hand control fully clockwise.
Good luck

Subscribers  do not see these advertisements

 

mrpickles

Free Member
Jun 5, 2020
1
3
swansea
Funster No
71,482
MH
knaus aclass
Exp
since 2000ish
hello i have the same model and had the same problem did the same as you then give up and called in the pros. He took out the yellow spindle temp control and it had indeed broke on the end please check again as its a common fault. if not i havnt a clue best of luck
 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
In your photo it seems like it is set to gas. Also the temp control is set very low.

I suggest that you set the left hand control clockwise to AES. Then set the right hand control fully clockwise.
Good luck

I can control the AES but not the temp control because it is stuck on low and I think this is the problem
 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
hello i have the same model and had the same problem did the same as you then give up and called in the pros. He took out the yellow spindle temp control and it had indeed broke on the end please check again as its a common fault. if not i havnt a clue best of luck

I definitely think it is worth another shot. The unit is easy enough to strip down. I did not fully remove the spindle when I carried out the inspection because it appeared to be in order

Subscribers  do not see these advertisements

 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
I have just stripped the control unit down again, withdrawn the yellow spindle and unfortunately, it was intact.

Back to square one and looking for advice?
Thanks
 
Apr 27, 2016
6,872
7,991
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
The yellow spindle turns slider on a variable resistor (potentiometer). Can you see if the slider moves round when the spindle turns, or is something broken inside it? The lights should turn on and off in sequence as the spindle turns.

Subscribers  do not see these advertisements

 

Vic. Parsons.

Free Member
Mar 2, 2015
415
1,970
Wales
Funster No
35,297
MH
Hymermobil S740
Exp
since 2014
Hi,
Just been looking at another Dometic fridge problem which seems to be a disconnected wire.
The picture of the wiring in the back of the fridge look remarkably like yours only there is a brown wire disconnected which in your picture is connected to the red in the large white terminal block.
I notice that in your picture there is no white wire coming from the grey sheathed wire, just the very end of it showing, which is present and connected in @PaulandPippa 's picture. (I would put a link to their thread if I could). Seems like the two problems may be related.
Is there a white wire hanging loose at the bottom below the black relay?
 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
The yellow spindle turns slider on a variable resistor (potentiometer). Can you see if the slider moves round when the spindle turns, or is something broken inside it? The lights should turn on and off in sequence as the spindle turns.

Hi Autorouter,
The spindle is intact and whilst the white slider moves around, the light remains on one bar (lowest setting)

I am baffled by this and assumed the PCB was faulty. I have priced a new one up but was shocked at the price being £255.
Regards
Tim
 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
Hi,
Just been looking at another Dometic fridge problem which seems to be a disconnected wire.
The picture of the wiring in the back of the fridge look remarkably like yours only there is a brown wire disconnected which in your picture is connected to the red in the large white terminal block.
I notice that in your picture there is no white wire coming from the grey sheathed wire, just the very end of it showing, which is present and connected in @PaulandPippa 's picture. (I would put a link to their thread if I could). Seems like the two problems may be related.
Is there a white wire hanging loose at the bottom below the black relay?

Hi Vic,
I will check out the wiring tomorrow and let you know.
Regards
Tim

Subscribers  do not see these advertisements

 
OP
OP
Toady
Jan 1, 2019
758
1,424
Pembrokeshire
Funster No
57,780
MH
Hymer B704 PL
Exp
Since 2017
Hi,
Quick update:

Dometic engineer attended house today and examined fridge. It was as I thought, a new PCB required. As soon as it was changed everything kicked in.

There was also one other fault he found. The connector into the grey ignition burner was faulty which was causing the gas igniter to be temperamental. He said this was a common fault and rather than change the loom (big job) he fitted a spacer in between the clip and igniter burner box. This put pressure on the connections in clip....hey presto...job done.

Thank you all for your help and guidance. Damn these fridges test you.
Kind Regards
Toady
 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Latest journal entries

Funsters who are viewing this thread

Back
Top