Trailer connection for Jayco 12 Pin plug

[john_paul_128]

Hi All,

I wanted to post this diagram in hope that is useful to others wanting to connect a Jayco caravan with 12 pin flat plug to Discovery 4 12N/12S plugs. I can confirm that it works perfectly for my Jayco Expanda.

I am not an auto electrician and the diagram is based upon my own research and discussion with Jayco. Please use at your own risk!

My domestic fridge draws 12 amps and is well within the limits of the fridge wiring on the 12S plug, but if you have a much larger fridge this would need further consideration.

With thanks also to Colin Pedersen for his LED light digram posted on the site.

Rgds, John

[john_paul_128]

Hi All,

I wanted to post this diagram in hope that is useful to others wanting to connect a Jayco caravan with 12 pin flat plug to Discovery 4 12N/12S plugs. I can confirm that it works perfectly for my Jayco Expanda.

I am not an auto electrician and the diagram is based upon my own research and discussion with Jayco. Please use at your own risk!

My domestic fridge draws 12 amps and is well within the limits of the fridge wiring on the 12S plug, but if you have a much larger fridge this would need further consideration.

With thanks also to Colin Pedersen for his LED light digram posted on the site.

Rgds, John

There was an error in the original diagram - pls note updated version.

Rgds, John

[taffy]

Where did you get the 12 s Plugs

[rufusking]

Your diagram shows pins 5 & 7 going directly from the 12N to the flat plugs 5 & 7. As listed in the pin assignments at the bottom, 5 on the 12N is a tail light circuit but on the 12 flat is the brake controller wire.

I think it is pin 11 that has a assignment for the rear fogs (pin 2 on the 12 N) but this is very rarely used in AU.

I would bind both power circuit grounds (pins 3 & 7 on the 12S) to pin 10 rather than to the ground used by the lights (pin 3).

Might be worth moving this into the FAQ's after everyone has reviewed it.

[rufusking]

Where did you get the 12 s Plugs

Just check eBay, plastic or metal around $12 delivered. Make sue you search is set to worldwide.

12S 7-Pin Supplementry Towing Plug for Caravan electrics | eBay

[samandfee]

Hi Guys

Just to let you know john pauls plug set up works fine on our Jayco swan outback to Disco 4....great work.......

samandfee

[RickO]

Your diagram shows pins 5 & 7 going directly from the 12N to the flat plugs 5 & 7. As listed in the pin assignments at the bottom, 5 on the 12N is a tail light circuit but on the 12 flat is the brake controller wire.

I would bind both power circuit grounds (pins 3 & 7 on the 12S) to pin 10 rather than to the ground used by the lights (pin 3).

Hi rufsking / John,

Forgive what may be obvious questions but can I ask:

1. if you are identifying that that 12N pin6 needs to be wired to the 12 flat pin5?

2. why do you suggest that that 12 flat pin 10 be used - due to it being rated higher?

3. will a pulse buster be required if the 2014 Jayco Expanda van I have just ordered has LED tail lights?

Thanks a mil,
Rick

p.s. awesome work guys!!

[ADMIRAL]

[QUOTE=RickO;2162288]Hi rufsking / John,

Forgive what may be obvious questions but can I ask:

1. if you are identifying that that 12N pin6 needs to be wired to the 12 flat pin5?

2. why do you suggest that that 12 flat pin 10 be used - due to it being rated higher?

3. will a pulse buster be required if the 2014 Jayco Expanda van I have just ordered has LED tail lights?

Thanks a mil,

You don't need it for the LED lights, just the trailer tow functions.
Buy yourself one of the commercially available LED resistors ( Repco sell the Narva unit ) wire it between one of your indicator wires and earth on the van frame. The Disco will detect the circuit is correct at start up. The trailer icon will only come on when the indicator the resistor is wired to is selected, but don't worry. The trailer function has been selected, and it will all work correctly.

[tiddy]

Hi all, don't mean to hijack this, but some advice is needed, my wife & I have just purchased a MY14 Discovery & I will use the LR supplied hitch. I purchased a Hayman Reese tongue & ball etc, but I'm not sure what the two electrical connectors are for.

Can a standard box trailer be plugged straight nto the car?...as you can probably tell, towing, trailers & connectors is not up my alley.

Thanks for any help.

[rufusking]

Hi RickO,

1) Pin 6 on the 12N (Black plug) is for the brake lights, so yes it is needed and goes across to Pin 6 (NOT 5) on the 12 pin flat . Pin 5 is for the electric brake controller if fitted.

2) For the trailer lights there is an earth/ground at Pin 3 (12N and 12 flat). For the higher current loads the 12S provides two seperate grounds (Pins 3 and 7) but on the 12 flat there is provision for only one at Pin 10. All of the grounds go back to the same body stud behind the lefthand compartment in the cargo area.

Hope that helps and clears things up.