Fridge no longer seems to work whilst towing after new battery!

[Jon_374342114]

I have had a bailey Scorpio for around 6 years and the leisure battery was dead when I bought the van. however, as we always use hook-ups I never bothered with it.

Recently the old battery started to leak so I replaced it with a new one but now I don't think the fridge works whilst towing. It used to work fine when the fridge was switched to battery - the red switch flashed every couple of seconds when the car engine was running. Now the red light doesn't flash whilst the engine is running and after a recent long trip the fridge had defrosted when I arrived.

Can anyone offer any suggestions and is there a way to test if the car powers the fridge without leaving it connected and the engine running for a couple of hours! I am not great with electrics!

Thanks

Jon

 

[rayc]

Jon, Step 1. With the engine running check for 12v(+) on pin 6 of the car grey socket with (-) on pin 7.

Step 2. Switch on the van 12v lights. Connect the car to the van and the fridge 12v lamp should come on, and after a short delay the van lights should go out.

let me know how you get on.

Ray

 

[rayc]

Jon, Step 1. With the engine running check for 12v(+) on pin 6 of the car grey socket with (-) on pin 7.

Step 2. Switch on the van 12v lights. Connect the car to the van and the fridge 12v lamp should come on, and after a short delay the van lights should go out.

let me know how you get on.

Ray

jon, When I first read your post I thought that it was 6 years old but see that it is a Scorpio so may be older. If it was pre 1997 check for 12+ (v) on pin 2 with the (-) on pin 3 at the car grey socket with the engine running. Disregard all info about internal lights and just check for 12v at the fridge when the van is connected and engine running.

 

[GeorgeB]

Jon,

Fitting a new leisure battery will have absoutely no affect on the fridge when you are towing.

1 , have you changed tow car recently? if you have check that the 12s socket wiring is correct to the age of your van, remember they are wired differently for pre & post 1998 caravans.

2. if you have not, then check the van & cars plugs & sockets, make sure that the pins are clean & bright, check also for any signs of overheating of either the plug or the socket, if there are, change both of them.

3. check that there is power to the fridge when the engine is running, see below

From the Caravan Club's Towbar wiring information

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

 

[Jon_374342114]

Thanks both for your helpful advice and suggestions. It is a 1991 Scorpio and I haven't changed the towcar. I will check the towcar output and the condition of the connectors. Do you know where I can find a diagram which numbers the connectors?

I think I can probably do that with my rudimentary electrical knowledge! If there are no problems there I may need to come back to you for an idiots guide to checking power to the fridge!

regards

Jon

 

[rayc]

jon,go to www.westerntowing.co.uk on RH Information drop down select 12S

note this is for a post 97 van, where it says "ignition key on" assume that means engine running.

If your van is pre 97 ignore the wires on pin 6 & 7. The fridge 12v(+) is on pin 2 with the (-) on Pin 3

 

[rayc]

jon,go to www.westerntowing.co.uk on RH Information drop down select 12S

note this is for a post 97 van, where it says "ignition key on" assume that means engine running.

If your van is pre 97 ignore the wires on pin 6 & 7. The fridge 12v(+) is on pin 2 with the (-) on Pin 3

jon, Sorry slip of the brain and finger: If pre 97 the 12v (+) is on pin 6 with the (-) on pin 3 i.e there is no connection on pin 7.

 

[full timer]

hello there, the caravan battery should have nothing to do with the fridge whilst towing etc, sounds like the red switch you are reffering to that normally flashes is the fridge ignition switch which is for lighting the gas flame, some early fridges never had a switch on them for the 12v supply whilst towing, if they did it would also be a red one but would stay on all the time while your engine is running........Mark

 

[merc_374359650]

I too have a 91 scorpio. I've had a similar fidge problem. Turned out to be the 12v fuse located near the charger under the corner seat.

There are 3 12v fuses in mine. Assuming yours is the same , check the one with the red wires going into it. It's very easy to take the fuse out to check it and put it into the "spare slot right next to it as I did ( DOH ).

 

[rosies]

Hello Jon ,

If I can have my twopeneth , the red light you refered to could be the 12v fridge power supply , but I think it should be showing red all the time power is on from car to fridge when engine running . My guess is you have a Smartcom relay which has never been adjusted properly , that is , if the smart relay was cutting in and out all the time then you would get a flashing affect . Checking the 12s ( grey ) socket pin 2 with earth pin 3 , when you engine is running , will tell you whats happening . If you do not get any power on pin 2 ( 12v-14v ) then first check you inline fuse on you car which should be under the bonnet close to your battery . Again if fuse ok then its possibly the smart relay ( or whichever relay fitted ) , if its a smartcom relay then maybe , and only maybe you can adjust it , look down the side and internally see a screw head , adjust this to point to approx the 3 o'clock position . If no luck then renew relay ( if its something like a hella relay then it also is fused ) . Good luck and hope this might help . ---- STEVE .

 

[CheapnCheerful]

Hmm. If you have one of these smart voltage sensing relays, it could be that you are experiencing extra voltage drop. When only the fridge was being powered, the voltage drop was not enough to cause the relay to drop out. But when a new battery is connected, the extra current drawn to charge the battery causes extra voltage drop and the relay drops out, and you get intermittant power to the fridge.