Rear Power Sockets

[Bretto333 Lurker Find all posts View Profile Close Bretto333]

For all the smart people out there...
I have a problem with my 07 GXL interior rear power sockets. Merit and cig sockets installed in vehicle.
- There is definitely power at the sockets, both my merit and cig sockets - checked with a multimeter with no key in ignition 12.4volts
- If I plug in a new cig plug or merit plug with no wires fitted to them - there is power at both + and - terminals within the plug (cover removed)
- I connect the fridge (35 litre 3-way fridge) wires to the cig or merit plug and nil power to the fridge - multimeter probe into wires shows no power
- If I remove the wires connected to the plug, there’s power again at the terminals within the plug
*the fridge cable is hard-wired to the back of the fridge
*fuses all checked and are fine
*checked fridge with cig plug in wife’s RAV4 and all works fine, power at wires (checked with multimeter probes)

Why does connecting the wires to either the cig or merit plug, take the power away???
PLEASE HELP!!!???!!!

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

Because your multimeter has high impedance so it's applying no load to the circuit. As soon as you put a load on it the high resistance fault you have shows up.

[Bretto333 Lurker Find all posts View Profile Close Bretto333]

How do I test for this? What’s the fix?

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

How do I test for this? What’s the fix?

Use a test light with an incandescent globe - not a LED type one or test it with the multimeter with the fridge in circuit

[sparksy Senior Member Find all posts View Profile Close sparksy]

What size cable is supplying the socket. A 3 way can draw up to 16A when switched to 12v. The cable might not be large enough and what you are seeing is voltdrop or as Adrian suggested you have a high resistance fault in the wiring. Check each joint for corrosion etc also If its protected by a circuit breaker , they have ahabit of going high resistance at higher currents. Replaced mine for that reason.

A way of checking how good joints or fuses/circuitbreakers with regard to voltdrop is to measure voltage across the joint or connections. Anything more than a few millivolts will indicate a problem. Best to do this under load. Thats how I found the dodgy circuitbreakers , I was losing over 0.5v across the terminals.

[Bretto333 Lurker Find all posts View Profile Close Bretto333]

So today I tried a few more things...
Resistance at cig plug (disconnected from car) is around 2.5
I tested another device in rear socket - no power even though multimeter says there is when nothing is plugged into it.
Plugged fridge into front cig socket, turned on acc. And there is power in the cable, 10.5v.
Left accessories on for two hours, fridge still not cooling.

[Bretto333 Lurker Find all posts View Profile Close Bretto333]

Back of fridge...

[sparksy Senior Member Find all posts View Profile Close sparksy]

So today I tried a few more things...
Resistance at cig plug (disconnected from car) is around 2.5
I tested another device in rear socket - no power even though multimeter says there is when nothing is plugged into it.
Plugged fridge into front cig socket, turned on acc. And there is power in the cable, 10.5v.
Left accessories on for two hours, fridge still not cooling.

Are you plugging it into the factory 12v outlet.
Also the fridge will take up to 12 Hrs to start cooling. Its a absorbtion fridge not compressor so has to get the liquid warm enough so it will start flowing.

At top of the fridge is a small chimney, check after a while to make sure that there is warm air coming out.

[GeeWhizz Senior Member Find all posts View Profile Close GeeWhizz]

First, almost all electrical faults occur in connectors/connections. Since you can make the fridge work in your wife's car the fault is not likely to be in the fridge or its cable/plug. With the fridge plugged in and accessory power on, check the voltage on the 'live' pin of the cigar socket and a good metal chassis point. Earth (chassis) connections have a habit of going faulty - remember Holden and Ford tail lights going off when the brakes are applied?

Since your vehicle is 13 years old, corrosion in one of the connections is likely. Where is the fuse for the power outlets? This is the most likely place for water to get in and cause corrosion. If its under the bonnet, then remove the fuse and have a close look at its contacts and the fuse socket contacts. The same story, but less likely, if the fuse is located inside the vehicle. Try replacing the fuse (use the correct value of fuse - you want it to blow if you introduce a short circuit during your testing) - it may have gone (relatively) high resistance.

If the fault is not in the fuse contacts or ground connection then it is most likely to be in one of the connections between the front of the vehicle and the power socket at the rear. There could be two or three (or more) connectors between wiring looms that may be where the fault is located.

To go much further, you'll need an electrical wiring diagram for your vehicle to determine which connectors supply power for the outlet/s.

With a 13-year old vehicle, I'd be tempted to run a new 15 or 20 amp rated wire from the fuse box to the power outlet if nothing else has worked.

[Pedro Advanced Member Find all posts View Profile Close Pedro]

Worth reading https://www.fridge-and-solar.net/wire.html by Colyn Rivers.
I am no expert but tend to agree with Sparksy re cable size.
You will note in above article that suggested size is 6 B&S cable is required.
This is what I have running from main battery and connected to 2nd battery in rear to power my Waeco CF50
This photo shows initial fitting of cable to battery via anderson plug





Since then I also added Solar to roof of and it has cable running through to feed into this 2nd battery, also using 6 B&S.
Photo , which I took to show wiring through rear taillight , shows the Waeco on its slide


The battery box sits behind the Waeco as shown below and fits snugly behind 2nd row passenger side seat


I would get an auto sparky to advise you on the wiring to rear power socket

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

And I would urgently do something about securing that battery box. 25kg + of flying battery is a serious threat to life in even a minor accident.

[Pedro Advanced Member Find all posts View Profile Close Pedro]

And I would urgently do something about securing that battery box. 25kg + of flying battery is a serious threat to life in even a minor accident.

This is one side view and battery is well secured.

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

Excellent