Fridge not working on 12v - how do I find the fault?

[Louis_5040937]

I have just returned from a weekend away and couldn't get the fridge to run on 12V.

For example, I connected up both sets of electrics fine

The brake / indicator lights work fine on the van but before I pull away, I decided to check whether the fidge 12v light was on - it wasn't but I had little choice but to contine. Arrive at destination with a warm fridge. Same on the journey home.

The van is brand new (Bailey Ranger) and I've only had the car a couple of months. The question is, how do I find the fault? Logic says to start with the grey socket on the car's tow bracket to ensure that the power's coming through. I have a volt meter but how / what do I test ?

I know I can go back to the dealer if there's a problem with the ven but I thought I'd start with the car first.

 

[rayc]

Louis, As your van is post 98 then it requires 12v+ on pin 6 with - on pin 7. The easy way to check this voltage is present is to hitch the caravan up without the ignition on and the engine running. Switch on the 12v lights in the caravan, start the car engine and the lights should go out. (The reason for this is that the fridge supply also operates a relay in the van that switches the van internal 12v electrics off and switches the permanent feed on pins 4 + and 3 - to charge the caravan battery).

If the van lights do not go out then check for the voltage on pin 6 & 7 which should be present when the engine is running.

 

[JimC]

Hi Louis

You say you have only had the car a couple of months,do you know how old the tow bar and more to the point how old the wiring is to the grey 12s socket.If its pre August 1998 then the wiring may not match your new Bailey.I believe the later caravans require a separate refrigerator earth wiring to pin number 7

This should be a separate earth to a good earth point on the chassis, and not linked to the earth on pin 3.

Regards Jim

 

[Louis_5040937]

Jim

Thanks for the reply. The car's an 03 soI would hope it has up to date electrics! Cheers Louis

 

[colin(bridgend)]

The 12 volt supply will not be sufficient to make the fridge go cold from rest. It is advisable to either run the fridge for at least 24 hours on mains voltage prior to setting out or alternatively bring the fridge to cold on gas and then convert over to 12 volt to maintain the required fridge temperature.

 

[ProfJohnL]

The 12 volt supply will not be sufficient to make the fridge go cold from rest. It is advisable to either run the fridge for at least 24 hours on mains voltage prior to setting out or alternatively bring the fridge to cold on gas and then convert over to 12 volt to maintain the required fridge temperature.

Hello Colin

I agree that it makes good sense to cool the fridge down using mains or gas prior to travelling, But I am not sure of, is your logic when you say the fridge won't go cold on 12V. It does not matter which form of power you use, they all provide heat to the system refrigerant system and as such all will eventually cool the fridge down.

I accept that 12V dc power will only usually available when the car engine is running, and it may not be on long enough to achieve the required reduction in temperature during the journey, but given a long enough journey it would cool down.

 

[Louis_5040937]

Guys

Thanks for the advice.

There is no voltage reading between pins 6&7 so at least it seems as it's the car that's the problem. Would there be some sort of fuse that could have blown? I've looked at the car's fusebox but there's nothing obvious?

 

[rayc]

Louis, As you havn't got the voltage on pins 6 & 7 can you check the permanent feed on pin 4 + with - on pin 3. This should be there all the time no matter whether the engine is running or not. If you havn't then it would appear that the supply fuse has propably blown. If you have then the fridge relay in the car has a problem. The supply fuse may be a bit difficult to find because it depends where the fitter put it. In my Mondeo it was in the footwell of the front passenger behind the carpet, in my CRV it is behind a panel by the steeering wheel. Sometimes it is adjacent to the battery. If you know who fitted the towbar, perhaps there is a sticker then give them a ring.

 

[Louis_5040937]

Louis, As you havn't got the voltage on pins 6 & 7 can you check the permanent feed on pin 4 + with - on pin 3. This should be there all the time no matter whether the engine is running or not. If you havn't then it would appear that the supply fuse has propably blown. If you have then the fridge relay in the car has a problem. The supply fuse may be a bit difficult to find because it depends where the fitter put it. In my Mondeo it was in the footwell of the front passenger behind the carpet, in my CRV it is behind a panel by the steeering wheel. Sometimes it is adjacent to the battery. If you know who fitted the towbar, perhaps there is a sticker then give them a ring.

Ray, thanks for taking the time to reply. I get 12v between pins 3&4 so it looks as if it's the fridge-relay. Is it something that's user servicable? Am I likely to find it under the dash?

 

[Louis_5040937]

Ray, thanks for taking the time to reply. I get 12v between pins 3&4 so it looks as if it's the fridge-relay. Is it something that's user servicable? Am I likely to find it under the dash?

 

[Rayc1]

louis, As you have the voltage on pins 3 & 4 the next step is to find out why the fridge relay is not working. Firstly check that pin 7 (the fridge -)is going to the car chassis. You can do this by either checking continuity between pin 7 and chassis or by putting your meter between pin 4 and pin 7.

The relay is normally mounted in the boot behind one of the side trims. The + voltage (that you have on pin 4) operates the relay when the engine is running. When the relay operates it should feed the + to pin 6. The relay is normally, these days at any rate, a voltage operating device, that is it senses the rise in voltage when the car engine is running. It sometimes has an adjuster that you set. Just as a matter of interest have you ever used a post 98 van with your car? Are you sure the relay was ever fitted? Check where the RED wire from the car 12S socket is going. I'll look forward to hearing from you. Ray

 

[Louis_5040937]

Ray

Thanks for your continued advice.

Unfortunately, my multi-meter won't test continuity (and I don't know what it is anyway!) so I think I've reached the limit of my technical ability. Putting the meter between pins 4&7 gives no reading whatsoever.

Re using a post 98 van, the qanswer is that this is my first van and it's brans new. When I purchased the car, the tow-bar was already fitted so it could have been towing anything.

As it happens, I've got to take the rear trim out over the weekend to fit a dog-graud so I've got the opportunity to do some wire chasing. so I'll let you know what I find. I've asked a company (pct automotive ltd) re a replacement relay and they have advised me of a specific relay for the car for around

 

[rayc]

Louis, thanks for the update, it keeps the grey calls active. Continuity is the resistance so if you have an ohm setting on your multimeter that would have done. Pin 3 and pin 7 should both be connected to the car chassis. Pin 3 is as you get the voltage between pins 3&4 but pin 7 obviously isn't.

I suspect that the fridge relay has never been fitted or if it has it is for the pre 98 convention when fridge + supply was on pin 2 with the negative on pin 3.

Good luck with it, I hope the fridge is keeping the wine cool on route soon. Ray

 

[Louis_5040937]

Ray

I traced the wiring today and found the relay (it was behind the rear light cluster). Is there any way I can test it to see if it's faulty? (I don't know if it helps but it's a Ryder TF1170X Self-Switching Combination Relay).

Regards

Louis

 

[rayc]

Louis, Yes there are a couple of simple tests. First check and make sure that the Black wire (fridge -) which is going to pin 7 of the socket is connected to the car chassis.

If it isn't then for the fridge to work its got to!

Then check where the RED wire (fridge + supply) is going. Is it connected to the relay? If it isn't then its got to for the fridge to work.

Assuming the answer to the above is YES then check that the the RED wire gets voltage (meter between chassis and red wire) when the engine is running.

If you do not get this, or you find that instead of the RED wire going to the relay that the Blue is connected then check voltage between chassis and pin 2. If this gets voltage when the engine is running then the car is wired for pre 98 standard.

I hope this helps, let me know what you find.

 

[rayc]

Louis, I put Ryder TF1170 in google and was taken to www.rydertowing.co.uk/towbar_relay_technical/towbars_relays_TF1170. There are some good wiring diagrams and explanations to how it works. Ray

 

[John_5040664]

I haven't sifted through all the replies to this problem, but I have a suggestion that might help.

I used to get a similar fault until my father in law suggested that I check that the prongs on the connecting plug haven't closed up and broken the connection. They open up sufficiently if you insert, say, a penknife blade into the ends of the relevant prong. A bit of vaseline doesn't go amiss, either.

Worked for me - good luck.

 

[Louis_5040937]

Thanks for the responses Guys. Unfortunately, I can't do anything until the weekend - will update then. Louis

 

[Louis_5040937]

Graham

I think I've finally cracked it!!

Taking all the trim out again tonight, the black wire from the 12S socket (Fridge -ve) was not connected to anything (it was taped up!). I connected it to the car chassis and bingo - it all works. The one thing I did notice though was that on taking the 12S socket apart, I've been looking at the pin numbers from the front of the socket rather than the back as I understand you should. As it happens, it wouldn't have made any difference as the black wire wasn't connected anyway.

Thanks for all your help and advice on this one - I had been close to calling in a professional - you've saved me a few quid.

Louis

 

[Louis_5040937]

Ray - sorry, I got cross threaded with the TTG safety cameras one! I should have thanked you and not Graham!

Louis

 

[rayc]

Louis, I'm glad you have sorted it. It appears it was wired for a pre 98 van where pin 6 is +ve, with Pin 3 -ve. All the best, Ray

 

[Bri2]

Louis, my van is also a new Bailey Ranger and I recently, last week, had a problem with the 12v lights shorting out. Would you believe a small piece of insulation tape had come off a baynet connector, I shall be intouch with bailey over this one. After fixing the fault, I found as Ray states, the fridge should work with the cars engine running and the light are out with zero volts on the vans voltage gauge / switch. Engine off, no fridge, lights on. So check the 12S socket to start. Look at this link

www.caravanninglinks.co.uk/electricks_wiring_code.htm

Brian