3 way fridge issue

MicktheMan

Hi Folks,
looking for some pointers.
Have a 3way fridge in camper and it works fine on gas and mains. The issue is that it doesn't work (red light switch) doesn't light up. The fridge is an Electrolux in a 1999 camper.
Any ideas of what to check?
Thanks

Fairly common issue, usually the switch is burnt out. Could be the element, you can check that for resistance with a multimeter; 0Ω means it's kapput. Could also be fuse or wiring.
Most fridges are wired to the ignition via a relay so they won't work unless the engine is running.

Similar thread here

MicktheMan

Sir Liamalot wrote: »

Fairly common issue, usually the switch is burnt out. Could be the element, you can check that for resistance with a multimeter; 0Ω means it's kapput. Could also be fuse or wiring.
Most fridges are wired to the ignition via a relay so they won't work unless the engine is running.

Similar thread here

Thanks for post and link.
Yeah, I know engine has to be running for fridge 12V to work:)

I'm off to check a couple thing and will report back.

MicktheMan

Right so

I've checked the following:

There are 3 cables going into the switch (2 white, 1 brown), top white, middle brown, bottom white.

The switch seems to be working as resistance, voltage changes depending on switch position.
So first resistance:

0.6 ohm between top and middle pin when switch is in "off" position
0.6 ohm between top and bottom when switch in "on" position
all other combinations show open circuit

Voltage:

14.1 V between middle and bottom when switch in "off" position, 0V in "on" position
14.1 V between top and bottom when switch is "off", 0V when "on"

Comment; 0.6 ohm is probably contact resistance so am assuming element is the problem. Am I right? Could it be anything else? Where to get an element? Cost? Easy to get at etc?

Again, thanks for your help with this.:)

Yeah resistance sounds low. What wattage is the 12v element? Check the manual or online pdf if you aren't sure.
Middle pin is ground for bulb...probably common but not the best approach as it's likely parallel. You'd just be checking the bulb resistance.

Check top or bottom switch connector while switch is on and isolated fridge negative at the battery if you can find it, while battery is disconnected. You don't need to run the engine for this. Alternatively just try the + and - on the 12v chocolate block at the back of the fridge with switch on.

Easy enough get a new 'un
http://www.ebay.co.uk/sch/i.html?_trksid=p2050601.m570.l1313.TR10.TRC0.A0.Xdometic+12v+element+100w&_nkw=dometic+12v+element+100w&_sacat=0&_from=R40

Or Aidan_m_m usually has a stock you could try pm but I'm sure he'll be along shortly...mad for the fridges he is :D.

Could be working just very badly ie. bad ventilation, poor cable etc.
12v on those fridges is not the best.

Best disconnect the switch middle connector to isolate the element as it'll provide a path of least resistance.

MicktheMan

Sir Liamalot wrote: »

Check top or bottom switch connector while switch is on and isolated fridge negative at the battery if you can find it, while battery is disconnected. You don't need to run the engine for this. Alternatively just try the + and - on the 12v chocolate block at the back of the fridge with switch on.

I'm not sure what you mean here, can you elaborate a bit.

Thanks Sir:)

In order to check the element resistance you have to isolate it. Otherwise your meter will read the easiest path to ground. So any way you can resistance check the element and only the element will give you an accurate reading.
The ground on the switch bulb makes a parallel circuit with the element which will throw your readings out.

The easiest way if you didn't have to remove the fridge or you have easy access to the back would be to disconnect the element and probe that. Short of this you have to find a way to check the element and only the element.
Chocolate block = connector block; the main 12volt feed at the back of the fridge. You can probe here with the battery cables disconnected on both ends, ie, at battery posts and at fridge feed, the switch bulb ground disconnected and the switch on or with the switch off and probe the main fridge ground and the switched live terminal.
If you can easily isolate the fridge from the battery ie. you don't have a power distro/zig unit then you can possibly find the same negative wire at the battery posts this might save some time as you only need to get to the back of the fridge for the ground.

The easiest way I can think of is to remove the switch, probe the switch bulb ground and switched live (I think it's the bottom switch terminal but not sure) with the fridge 12volt supply disconnected before it goes to a common ground.

Clear as mud?

- Disconnect battery
- Isolate fridge from common grounds eg. disconnect 12volt + & - feed to fridge at rear.

Then
- Disconnect middle switch connection.
- Turn switch on
- Check resistance from connecter block + & -
or
- Disconnect middle switch connection -, and switched +
- Check resistance across the two switch wires (bulb ground and switched live) you've just disconnected.

MicktheMan

Got it:)

Hopefully I'll find the connector block easily.

Thanks again, really appreciated.

No worries, holler if there's any probs.
Careful of the gas lines if you are attempting to move it. If you can remove the vents outside they might help with access or at least tell you how much play you have.

MicktheMan

MicktheMan wrote: »

The switch seems to be working as resistance, voltage changes depending on switch position.
So first resistance:

0.6 ohm between top and middle pin when switch is in "off" position
0.6 ohm between top and bottom when switch in "on" position
all other combinations show open circuit

Voltage:

14.1 V between middle and bottom when switch in "off" position, 0V in "on" position
14.1 V between top and bottom when switch is "off", 0V when "on"

There's something funny about those numbers but I haven't decided what it is yet.
My advise is to remove the switch and check it for continuity not resistance (possibly the same thing on most meters but bare with me)

Remove the switch fully and try to retain the wires from popping back into the back of the fridge where you can't get them.

You ought to have no continuity on any pole which switch is open (off)
While switch is closed you ought to have continuity between live feed and switched live and switched live and bulb ground.
If this checks out try the wiring at the socket you just disconnected.
One white should be 12v+ between ground, brown should be continuity between the chassis/battery negative, other white should be 0v between ground with no continuity and should match the pin you established is the switched live.

Getting 14.1v between the top and bottom pin while it is off sounds to me like a wiring fault.

MicktheMan

Thanks Sir:)

I have been advised;) by Mrs Micktheman to down tools and leave it for someone who knows what they are doing:o.

I really appreciate all the help I got from you though and thanks again.

Mick

Try Aidan.

MicktheMan

Sir Liamalot wrote: »

Try Aidan.

:D:D

JonMac

I'm told Aidan is on holiday at the moment.

Aidan_M_M

JonMac wrote: »

I'm told Aidan is on holiday at the moment.

I am, but I'll be back in the garage in a few short days!

I just spent the day at the back of a fridge, that connector is a nightmare to get to. Not for the faint-hearted or short tempered.
The switch is easy test.

An easy temporary solution is to 12v power the AC element from the inverter. Plug the fridge AC plug into the inverter (provided the inverter is larger, to manage the load; 150watt+ inverter should be sufficient, my AC element is 105watt you can check yours in the manual) and operate it from the AC switch & element.