Electrics/fridge problem

[Steven_374359746]

Hi all,

New to this.

I have a Baiey pageant Moselle 1997 and today i started to prepare it for our first outing this year.

When i connected to car to test charging, electrics etc I got no response. Tried allsorts and finally found that if I removed the fridge fuse from 12v supply next to charger under seats that all was well with the world i.e. ampmeter showing charge in battery, lights working etc. As soon as I touched this fuse back to the fitting all power was drained.

Does anyone have any idea what might be the problem.

Thanking you all in advance for your help.

Steven

 

[JeremyClarksson]

When the car is connected only the fridge and battery charging should work on the internal caravan electrics, the other circuits would be removed by a relay of some sort - by removing the fuse you are probably removing the supply to the relay that achieves this and the caravan is back running on its own battery not the car.

Connect up everything including this fuse and start the car you should be able to get an increased reading across the van battery and the fridge should be working although this may be difficult to tell without measuring it.

If you want to check the internal caravan electrics disconnect the car and check with battery and mains connected.

 

[Charlie25]

I almost sure this is normal, your caravan will be fitted with a isolation relay which shuts of all power to internal electrics apart from the fridge and battery charging when your cars engine is running

 

[Steven_374359746]

When the car is connected only the fridge and battery charging should work on the internal caravan electrics, the other circuits would be removed by a relay of some sort - by removing the fuse you are probably removing the supply to the relay that achieves this and the caravan is back running on its own battery not the car.

Connect up everything including this fuse and start the car you should be able to get an increased reading across the van battery and the fridge should be working although this may be difficult to tell without measuring it.

If you want to check the internal caravan electrics disconnect the car and check with battery and mains connected.

Hi thanks for that.

However when this fuse is connected I do not get a reading on any curcuit. I.e. no charging going on.

When disconnected from the car, as soon as I put this fuse back in I lose all power elsewhere in the van. No lights no reading on the meter.

Fuse out meter reads Ok, lights work fine etc.

 

[Steven_374359746]

Hi Charlie

No battery charging going on and the 12v internal lights wont work either.

literally if this fuse is in place with the car engine running or not the reading drops to nothing on the meter.

 

[Charlie25]

Steven, At your 12s socket on the car do you have +12volts at pin 4 without engine running both Pin 3 & 7 should be an earth and when you start your car Pin 4 & 6 should have +12volts

 

[Steven_374359746]

Hi Charlie

Van is at work so I will check it in the morning and get abck to you tomorrow for more help and advice.

It has me totally stumped I'm getting to thinking that the wires to the fridge are earthing down somewhere and that is why I lose all power. I havent tried the 240 but will try that also tomorrow, see what effect that has on charging lights etc with the fuse in place.

As I say even when disconnected from the car as soon as the fuse is in place the whole of the electrics seem to go down!

 

[Steven_374359746]

Just a thought Charlie

Test on electircs from car showed 13.8v output is this enough?

if you don't know, (not wishing to insult you) does anyone else?

Steven

 

[Charlie25]

13.8volts is spoton but have you got power and earths as per my other post, your caravan requires 2 powered pins and 2 earthed pins. Once you know your towing vehicle is supplying the correct power and earths, then you can start tracing the fault in the caravan

 

[Steven_374359746]

Hi again Charlie and all others online,

Update on yesterday' problem.

Followed your advice to the letter and we have

Engine off 12.28v from pin 4. No voltage at pin 6. 3 & 7 Earth.

Engine on 14.2V Pin 4 & 6.

So everything seems OK at Car end of things.

Fridge is powering both from caravan battery (car disconnected) and 240v. So fridge is operational.

At my wits end could the cable from the A frame to the relay in the caravan be at fault or the relay itself?

Any Ideas?

Best regards and thank you for help so far we may make it for the Spring Bank away trip.

Steven

 

[Charlie25]

Steven, I would now re-check all the connections, fuses and 12s plug which can suffer from water damage . Also try locating the isolation relay and get someone to start the car while your in the caravan, you should hear it click as it switches.

Also not sure what you mean when you say fridge is powering from caravan battery with car disconnected, do you mean the gas igniter? The fridge should only work 12volt when towing

 

[rosies]

HELLO all , sorry for butting in , BUT on pre 1998 caravans there is no standard fit relay . All relays being fitted are to the tow vehicle , and the caravan should be wired up to pre 1998 spec . So by the looks of your situation Steven its possible you have a caravan internal wiring fault AND a vehicle wiring fault on what you have said . Please find follow wiring instructions for vehicle 12 s and 12 n , hope it helps .--- STEVE .

12N & 12S Sockets To Suit October 1979 to 31 August 1998 Caravans

TERMINAL COLOUR 12N SOCKET 12S SOCKET

1 Yellow L H Indicator Reversing Light(s)

2 Blue Fog Light(s) Caravan Battery Charging

(Ignition Controlled Supply)

3 White Return (Earth) Return (Earth)

4 Green R H Indicator Interior Lights Etc (Permanent Supply)

5 Brown R H Tail Light Sensing Device

6 Red Stop Lights Fridge (Ignition Controlled Supply)

7 Black L H Tail Light

& Number Plate Not Used

Notes

The supplies to 12S pins 2 and 6 must be installed such that they are live only when the vehicle engine is running (see Sections 3.5.13 and 3.5.15 below).

The supply to 12S pin 2 for caravan battery charging has been customary practice in the UK for many years. However, it has never been adopted into a British or other standard for towbar wiring. It is, therefore, frequently ignored by vehicle manufacturers in their wiring kits.

See section 3.5.16 for advice regarding 12S pin 2 if towing a continental-built caravan.

With the exception of the 12S pin 2 connection as mentioned above, sockets wired according to these specifications will comply with British Standard BS AU 149a (12N) and BS AU 177a (12S). These standards are effectively identical to International Standards ISO 1724 (12N) and ISO 3732 (12S).

3.3 1 September 1998 And Newer Caravans

These are built to European standards, one of which defines the 12V wiring, and results in changes to the 1 2S system. (The 1 2N system remains the same.) An extra earth acts to separate the fridge power supply from other circuits, minimising the risk of overloading the return wire when several circuits are used together. Battery charging is now officially included, but via pin 4, not pin 2, as was usual practice in the UK before, but never included in previous standards. Pin 4 also operates interior lights etc, but not at the same time as battery charging. Switching to achieve this is done in the caravan.

12N & 12S Sockets To Suit 1 September 1998 And Newer Caravans

TERMINAL COLOUR 12N SOCKET 12S SOCKET

1 Yellow L H Indicator Reversing Light(s)

2 Blue Fog Light(s) Sensing Device

3 White Return (Earth) Return (Earth) For Pin 4

4 Green R H Indicator Interior Lights etc or Caravan Battery

Charging (Permanent Supply)

5 Brown R H Tail Light Not Used

6 Red Stop Lights Fridge (Ignition Controlled Supply)

7 Black L H Tail Light

& Number Plate Return (Earth) For Pin 6

Notes

The supply to 12S pin 6 should be live only when the vehicle engine is running (see Section 3.5.15 below).

12S pins 3 and 7 should not be joined together at the socket. They should be taken separately to an earth point on the vehicle structure. Failure to do may increase the likelihood of overheating of the 12S plug and socket, especially if damage to pin 7 occurs (see section 3.5.17).

12S pin 4 must be permanently live for both battery charging and interior light etc functions to operate. The fridge circuit must work correctly for switching of the pin 4 supply between these functions to occur.

At the time of writing, the standards for vehicle wiring have not been updated to match the latest caravan wiring standard. The above specification complies with British Standard BS AU 149a (12N) and the effectively identical International Standard ISO 1724. BS AU 177a and ISO 3732 (12S) do not yet include the earth via pin 7, and hence this connection may be omitted by some makers and installers.

4. if all is in order & you still don't have power when the engine is running, then the VSR (volatge Sensitive Relay) that trigger & then supplies power has failed & needs to be replaced

 

[Charlie25]

HELLO all , sorry for butting in , BUT on pre 1998 caravans there is no standard fit relay . All relays being fitted are to the tow vehicle , and the caravan should be wired up to pre 1998 spec . So by the looks of your situation Steven its possible you have a caravan internal wiring fault AND a vehicle wiring fault on what you have said . Please find follow wiring instructions for vehicle 12 s and 12 n , hope it helps .--- STEVE .

12N & 12S Sockets To Suit October 1979 to 31 August 1998 Caravans

TERMINAL COLOUR 12N SOCKET 12S SOCKET

1 Yellow L H Indicator Reversing Light(s)

2 Blue Fog Light(s) Caravan Battery Charging

(Ignition Controlled Supply)

3 White Return (Earth) Return (Earth)

4 Green R H Indicator Interior Lights Etc (Permanent Supply)

5 Brown R H Tail Light Sensing Device

6 Red Stop Lights Fridge (Ignition Controlled Supply)

7 Black L H Tail Light

& Number Plate Not Used

Notes

The supplies to 12S pins 2 and 6 must be installed such that they are live only when the vehicle engine is running (see Sections 3.5.13 and 3.5.15 below).

The supply to 12S pin 2 for caravan battery charging has been customary practice in the UK for many years. However, it has never been adopted into a British or other standard for towbar wiring. It is, therefore, frequently ignored by vehicle manufacturers in their wiring kits.

See section 3.5.16 for advice regarding 12S pin 2 if towing a continental-built caravan.

With the exception of the 12S pin 2 connection as mentioned above, sockets wired according to these specifications will comply with British Standard BS AU 149a (12N) and BS AU 177a (12S). These standards are effectively identical to International Standards ISO 1724 (12N) and ISO 3732 (12S).

3.3 1 September 1998 And Newer Caravans

These are built to European standards, one of which defines the 12V wiring, and results in changes to the 1 2S system. (The 1 2N system remains the same.) An extra earth acts to separate the fridge power supply from other circuits, minimising the risk of overloading the return wire when several circuits are used together. Battery charging is now officially included, but via pin 4, not pin 2, as was usual practice in the UK before, but never included in previous standards. Pin 4 also operates interior lights etc, but not at the same time as battery charging. Switching to achieve this is done in the caravan.

12N & 12S Sockets To Suit 1 September 1998 And Newer Caravans

TERMINAL COLOUR 12N SOCKET 12S SOCKET

1 Yellow L H Indicator Reversing Light(s)

2 Blue Fog Light(s) Sensing Device

3 White Return (Earth) Return (Earth) For Pin 4

4 Green R H Indicator Interior Lights etc or Caravan Battery

Charging (Permanent Supply)

5 Brown R H Tail Light Not Used

6 Red Stop Lights Fridge (Ignition Controlled Supply)

7 Black L H Tail Light

& Number Plate Return (Earth) For Pin 6

Notes

The supply to 12S pin 6 should be live only when the vehicle engine is running (see Section 3.5.15 below).

12S pins 3 and 7 should not be joined together at the socket. They should be taken separately to an earth point on the vehicle structure. Failure to do may increase the likelihood of overheating of the 12S plug and socket, especially if damage to pin 7 occurs (see section 3.5.17).

12S pin 4 must be permanently live for both battery charging and interior light etc functions to operate. The fridge circuit must work correctly for switching of the pin 4 supply between these functions to occur.

At the time of writing, the standards for vehicle wiring have not been updated to match the latest caravan wiring standard. The above specification complies with British Standard BS AU 149a (12N) and the effectively identical International Standard ISO 1724. BS AU 177a and ISO 3732 (12S) do not yet include the earth via pin 7, and hence this connection may be omitted by some makers and installers.

4. if all is in order & you still don't have power when the engine is running, then the VSR (volatge Sensitive Relay) that trigger & then supplies power has failed & needs to be replaced

Sorry steven, I overlooked the wiring change in 1998 as discribed in Rosies post.

 

[Steven_374359746]

Hi all,

I would welcome all and sundry to butt in, not that I dont appreciate help from any one source but that I need, with limited time, to sort this by next Friday! 7 days and counting!

Thanks Rosie for your input.

must have taken an age to type all that and so precise as well.

I suffer from woodblandness (sic) on the shortest of posts so to do that takes dedication.

Am I right in saying then from your post that I may just be lacking a 12v switched supply at pin 2?

How do I know if the earth is linked to pin 4 or pin 6?

And then if all is in order then what and where is the Voltage Sensitive Relay? Is that the thing under the bench seat next to the battery box?

A lot of questions I know but thanks again for any help.

Steven

 

[Colin_374358138]

I've just read your original post and am not sure exactly whats wrong...

When the car is plugged in and running the habitation relay turns everything off (almost).

All that will run is Fridge on 12V and batt charger. Your voltmeter id prolly turned off too. It doesn't mean theres no juice in your batt.

If you have green pin 4 connected you'll also get some internal lighting too I think. Green is now switched feed outta your relay. Blue and red (2 and 6) are both switched in the voltage of the car....

You just need to go thru it all bit by bit. Earthing, connections, maybe try a new relay, change the 12s plug and socket etc etc... measure the voltage drop thru the car, across the 12s, thru the caravan etc....

 

[Steven_374359746]

Hi Colin

This actually sounds pretty familiar.

So long since I tried it I'm now forgetting where I actually started!!!

When I connect car Volt meter Should drop?

But I think as Rosie said I have wired for Post '98 rather than pre '98 so I need to put switched supply to pin 2.

you mention trying a new relay, where? in the car or under seat in caravan? Car is 07 plate so would be suprised if at fault.

Will try volt drop as suggested and also charlie's suggestions of fuses etc.

After of course checking pin 2 voltage.

Time for bed a more sweet caravanning dreams. will update tomorrow

Thanks all

Steven

 

[rosies]

Hi lads , no Steven I am not that dedicated , all that tech/spec was from a electrical site that I just copied and pasted from when I saved it in MY documents , for my own use . So I giggled a bit at that one LOL .

I would also suspect your car being wired up to the latest spec ( post 98 ) but the caravan being pre 98 , no problems just that your pin 2 , on tow vehicle 12s socket will probably be dead/0 volts . To check your 12s or 12n sockets its best to use a multi meter on 12v dc . To check earth pins use the return ( - ) lead to earth pin (s) . So with engine running test pin 2 with red ( + ) lead , through multi meter and black (-) lead to pin 3 earth , if working you should get about 13.8 volts . That is your battery charge circuit .

The same method for testing pin 6 , + red lead to pin6 and - black lead to pin 3 earth . If you also try - black lead to pin 7 when doing this it will tell you if your car is wired up pre or post 98 . note:- pin 6 is for operating the fridge .

As for voltage sensative relays , these are commonly known as SMART relays , they dont need a feed from the alternator to operate them , they sense voltage change and operate to suit , and no you dont have a smart / VSR in your caravan , unless someone has fitted one ????????? .

What you should have is a permanent 12v supply on pin 4 which when coupled to the caravan works all internal 12v equipment ALL of the time regardless and separately of caravan battery .

At the moment I am at a loss as to why removing the fridge fuse you get power to 12v equipment and when you replace the fuse 12v power ceases !!! odd one that one . Anyway your are the man , hope you bottom it , good look ------- STEVE .