Broken fridge - please someone explain like I am 5 how to test it?

S

Sooshark

Active Member
Joined
20 Apr 2016
Messages
50
Location
London
Visit site
Hi

I am completely useless with electronics, happy to learn but basically not prior knowledge before living on a boat and they proper confuse me.

I am currently on shore power and woke up this morning with no fridge. I am a live aboard and not had any issues with it before. I have been doing some boat work so have been fiddling about with stuff.. not really anywhere near the fridge but seems too coincidental for it to break now?! (although everything else is breaking... stuff comes in 3s right?)

I have a digital multimetre to hand.

Please! How do I test if there is power coming from the battery? How do I test different points of the fridge?

I changed the fuses this morning but that didn't help. It does have a rather old toggle switch but this is doing nada at the moment.

Please help and be gentle! Thank you !
 
You need to check power to the thermostat first, power in and power out, these are the most common failure point, will Look a bit like a switch with single power in and single power out. Turn the temp knob to full low temp and back and you should hear it click as well
 
First check is to find the 12 volt supply wires where they are connected to the fridge, and check the voltage there. Second check is to see if the thermostat is working. Assuming the fridge has warmed up, turn the thermostat knob towards its warmer settings and listen for the click, then turn it back towards cold and listen again for the click. If there is voltage at the fridge and the thermostat contacts are closed so that it is demanding cooling, and the fridge compressor does not start then you need professional help.
I have opened up the control box on my boat fridge and re-soldered a broken connection, but I dion't think you want to go there. 12 volt fridges are tricky devices, they have a brushless motor which is controlled by a clever little box of electronic trickery that feeds its windings with pulses of current thus allowing it to run without needing brushes, which would be a source of failure in a completely sealed unit.

EDIT: Daverw beat me to it on the thermostat.
 
is this where the wires go into the back of the fridge. struggling to access it and trying to work out how to pull my boat apart in order to get to it
 
Daverw said:
You need to check power to the thermostat first, power in and power out, these are the most common failure point, will Look a bit like a switch with single power in and single power out. Turn the temp knob to full low temp and back and you should hear it click as well
Click to expand...

No clicks.

No light on in the fridge when it is open so indicates there is no power?
 
Check for a fuse near the compressor controller and then power to the controller box, should be marked as +12v in
 
Daverw said:
Check for a fuse near the compressor controller and then power to the controller box, should be marked as +12v in
Click to expand...


Is this where the wires go into the fridge?

At the moment I can't get to it. And the silly thing is wedged in, with poor design stopping me from just sliding it out. Trying to work this out.
 
Sooshark said:
is this where the wires go into the back of the fridge. struggling to access it and trying to work out how to pull my boat apart in order to get to it
Click to expand...
Apologies if you already know this, but the workings of the fridge (already mentioned as the compressor) is likely located separately from the fridge box. Look for the compressor in a cupboard perhaps. It’s the voltage input there that is being referred to in earlier advice. Sometimes a poor connection or bumped wire prevents the compressor getting its full voltage.
 
Venus1 said:
Apologies if you already know this, but the workings of the fridge (already mentioned as the compressor) is likely located separately from the fridge box. Look for the compressor in a cupboard perhaps. It’s the voltage input there that is being referred to in earlier advice. Sometimes a poor connection or bumped wire prevents the compressor getting its full voltage.
Click to expand...

You can assume I know nothing..

Right I’ve managed to get the fridge out!! That’s an achievement in itself after years of failing. Ok so it looks to me like the compressor is on top of the fridge. Here some photos (as you can see yes very old....)

Thank you all for help so far

IMG_4040.jpg

IMG_4041.jpg
 
If you look to the LHD side of the terminal connectors you will see the labels for the terminals, first check the +12v supply, set meter to DC voltage range at least 20v, put the black probe onto 0v wire and the red onto +12v and see what you read.
 
Looks like there's onle two big plus and minus', so stuck em in and it reads 1.78... Doesn't seem right?! As I said in previous post, assume I know nothing :)

Photo also attached in case i'm being stupid


IMG_4042.jpg
 
You have no power, it could be +ve or 0v, can you reach anything else that has working power or battery terminals, then you can put Planck probe on 0v and try the red connection again, then check it the other way,
 
Daverw said:
You have no power, it could be +ve or 0v, can you reach anything else that has working power or battery terminals, then you can put Planck probe on 0v and try the red connection again, then check it the other way,
Click to expand...

Okay ! Done that and one reads 13, and the other -13 ..... so that what does that mean?! Suggests perhaps the on off switch between the fridge and the fuses isn't working?
 
Did you mean the red connector on terminal 2 on compressor, red probe to 0v on battery black probe reading 13v?
 
Sorry.. so if my black probe is in the + terminal on compressor, and my red probe touches the negative next to fuses for my water pump.... then I get a reading of 13v... (although I just did it again and it was 15v)

When I put my proves on the fridge side of fuses (which come after a switch) I get a reading of 1 or 2... so seems like it could be an issue with the switch/fuses ?
 
Yes it does seem to be fuse or switch, if you have red probe on +12v terminal at compressor and black on negative near fuses and get 13v that would show power at compressor but negative fault, option would be to disconnect both at compressor and to run cable direct to compressor terminals from battery, black first and then red, I suspect compressor would run.
 
You must log in or register to reply here.

Share this page

Top