12S plug and socket - connections for fridge

[KeithJ]

I am looking to double up on the pins used to run the fridge when towing. This subject has been discussed before on this forum, and appeared in PC magazine - the problem being that the current drawn for modern, larger, fridges causes the normally designated pins to overheat.

I have read that the spare number 5 pin can be linked to the central, black, number 7 to supplement the earth for the fridge. This is no problem because the number 7 on my car is already connected to earth.

The advice also said the live to the fridge (number five) can be connected to the spare number 2 pin, which was formally used to charge the battery, and is normally still connected to the split charge relay on the car.

So, since the 5 and the 2 are both connected to the split charge relay, and therefore only live when the engine is running, they can both provide the live for the fridge, and spread the load, thereby preventing overheating.

My problem is, I have checked the 5 and the 2 on the car socket and whilst the 5 only becomes live when the engine is running, the 2 is live as soon as the ignition is switched on, before the engine starts. I would appreciate it if anyone can tell me if this setup is normal, and if so, is it still OK to link these two pins together.

Thanks

Keith

 

[Chris_374413356]

I suspect it is not a good idea to parallel the supplies as each comes from the same supply, obviously, but via different routes and fused differently.

I think the easy option is to ensure the plug pins are kept clean and gently spread the pins to maintain a good contact, this would stop the over heating due to bad pin contact.

I'm sure if you check this regularly all will be well with the fridge.

 

[Dustydog]

Keith

Here's the solution. You don't say how old your outfit is so just watch that point when reading the script.

http://www.towitall.co.uk/faq/faq1.htm
Cheers

Dustydog

 

[SirRogerFFS]

Hi Keith.

I have just been on the same route as you but when I came to check my plug on the tow vehicle I found that the two wires for fridge earth and live were not there.

If you look on page two of techinical have a look at Sir Roger Needs helpand follow Sprockets link you will find ..a full wiring code.

I cant see why there shold be a problem it should blow if there is a problem.

only that on the car pins 9 and ten are for fridge and earth

and if the correct fuse is used .

I hope this helps

Sir Roger

 

[KeithJ]

Thanks Dusty and Sir Roger

I have checked that the red (6) and Blue (2) on the car socket are both connected to the same source on the split charge relay.

Also that the black (7) and brown (5)are both earthed on the car.

I have spoken to Towbars and Trailers, who wrote the advice on the Towitall web site, and they confirmed that it is ok to link the red to the blue, and the black to the brown on the caravan plug. They said doing the earth connection alone is normally enough to cure the overheating problem because it is the middle pin that burns. (Sorry I got a bit mixed up with the pin numbers on my original post - the result of not looking at the wiring diagram!)

Thanks Chris, also - I am going to change the plug for good measure.

Keith