Well you learn something every day. Seven pin plug for the vehicle.

I have a 2011 Isuzu Dmax.

Yesterday I took some rubbish to the tip here on the central coast. Unfortunately I damaged the 7 pin plug on the car.

So bought a plug on the way home and went to fit it today.

When I took the cover off and exposed the inside I found it had 9 pins inside and the standard 7 on the outside. There are 7 standard pins and a slot either side of these 7 pins to take the wires for the LED lights.

So, back to the shop and asked for a plug that matched mine. Well the first two places had never seen one like it before.

Finally found a bloke who knew what it was. It appears that the 2 extra pins relate to the LED lights on your vehicle and there is a sensor strip and some resistors or the like in the plug.

Much to my horror I found that if the plug is not connected the back lights, brake and indicator lights won't work.
I went out to the car and sure enough the lights didn't work until I put the plug back on.

Repco finally found out what I needed and I pick it up tomorrow. A bargin at $27.

Evidently a lot of european and japanese late model cars have this sort of plug.

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Reply By: Member - Toyocrusa (NSW) - Tuesday, Mar 06, 2012 at 20:30

Tuesday, Mar 06, 2012 at 20:30
Wow Boo Boo. The wonders of modern technoligy. Makes a bloke wonder where all this stuff will end. Bob
AnswerID: 479668

Reply By: DMH122 - Tuesday, Mar 06, 2012 at 21:45

Tuesday, Mar 06, 2012 at 21:45
I think u will find the extra 2 pins are for disableing reversing sensors when connecting a trailer.
AnswerID: 479687

Follow Up By: Member - Boo Boo (NSW) - Tuesday, Mar 06, 2012 at 21:49

Tuesday, Mar 06, 2012 at 21:49

Yep I found out they did that as well, but didn't want to confuse myself. lol

I saw the diagram for that and the wire that goes from one pin to another I will have to run to one of the outside slots.

I am just happy to find what I needed after only an hour or so of looking.

FollowupID: 755139

Reply By: Ross M - Tuesday, Mar 06, 2012 at 22:58

Tuesday, Mar 06, 2012 at 22:58
Between the two pins is a small magnetically operated reed switch.
The reed switch earths the reversing camera when the lid is closed eg. no trailer.

When opened the magnet in the lid is away from the reed switch and it therefore switches off the earth to the reverse camera.

The good thing with this is, if the trailer plug falls out and the lid shuts you can select reverse to see the problem. Neat hey!

What is the talk about it being for LED's????? What LED's where?
AnswerID: 479697

Reply By: Mark S (cns) - Tuesday, Mar 06, 2012 at 23:48

Tuesday, Mar 06, 2012 at 23:48
I have a 2011 d-max,

I had to replace my 7 pin flat after our 4 month trip, as the pin sleeves were starting to move inside the plug casing.
Anyway, had the same setup with the 2 extra wires each side of the main 7 pins.
Wondered what they were for, then just decided to wire up the std 7 pins and left the other 2 wires disconnected to see what happened.Well, nothing different happened and the 2 wires remain disconnected.

All the tail lights work fine on mine, although there are no LED's in the styleside tail lights. Only LED's I can see are indicators in the mirrors and they work fine too.

AnswerID: 479703

Follow Up By: Member - Boo Boo (NSW) - Wednesday, Mar 07, 2012 at 09:00

Wednesday, Mar 07, 2012 at 09:00

When the bloke at the trailer shop told me about led's etc I thought he was pulling my leg to start with, but as I said earlier I had the plug in my hand and turned on the lights and blinkers and I had no indicators or lights.

I put the 2 wires back in without the 7 standard wires and bingo I had lights and indicators.

It affects late model cars with led lights. My Dmax is a cab chassis fitted with a Pod that has led lights. The plug actually came with wiring harness on the vehicle.

FollowupID: 755163

Follow Up By: Mark S (cns) - Wednesday, Mar 07, 2012 at 10:40

Wednesday, Mar 07, 2012 at 10:40
That explains the difference then and why mine was not affected, as the styleside has std bulbs
My plug was also supplied factory fitted.
There you go, now I know!!

FollowupID: 755174

Reply By: Member - Boo Boo (NSW) - Wednesday, Mar 07, 2012 at 14:54

Wednesday, Mar 07, 2012 at 14:54
Well I fitted the new plug today and I now have tail lights and indicators, but no reversing lights.

I will ask the question on the Isuzu forum and see what I missed.

AnswerID: 479755

Reply By: Member - Kevin S (QLD) - Wednesday, Mar 07, 2012 at 18:02

Wednesday, Mar 07, 2012 at 18:02
Wife and I went to see out new Coromal off road pop top that arrived at the dealer yesterday from Perth. It has a 12 pin plug to cater for the new smart fridge. Sparky will need to combine my standard 7 pin with the Anderson plug wires to produce input for the new plug. Hope he understands it all. I don't.
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AnswerID: 479777

Reply By: Ross M - Wednesday, Mar 07, 2012 at 19:37

Wednesday, Mar 07, 2012 at 19:37
The trailer wiring for a vehicle is very simple and is just a matter of having the correct colour in the trailer wiring aligned with the vehicle supply circuits.
The reed switch in the newer type plugs appear to just be a means of switching the reverse camera system off when towing a trailer. Just that, nothing more, no LEDS.

The Dmax, I have one, and fitted my own towbar.
It too has the reedswitch to cut off the reverse camera. None fitted.
However, the Dmax towbar has two relays which run off a power feed wire already in the vehicle loom.
On the indicators, the wires which usually go to the plug to run the indicators now go to a dedicated relay. One for each side indicator. The vehicle makes the relays switch on and off and the relays for RHS or LHS are switched on by the vehicle.
The output of these relays now run to the plug in place of the original wires. This powers the indicators on the trailer so it can handle the extra numbers of indicator lights which may be on some big caravans without altering the flash rate of the vehicle.
Has nothing to do with LEDs though.
All these items are just electrical devices which require a power feed, lamps, LEDs, all the same.
Theer is nothing mystical about this and it seems some people are being advised by staff who "do not know"about LEDs or indeed anything electrical.
AnswerID: 479789

Reply By: Member - Boo Boo (NSW) - Wednesday, Mar 07, 2012 at 21:41

Wednesday, Mar 07, 2012 at 21:41

I have read your posts a few times, mainly because I know how to do 7 pin stuff, but a bit puzzled by what your saying, and what happens when I take the old plug off and put it back on then put the new plug on exactly the same way.

I' sorry but I don't understand what you mean regarding the indicators. My indicator wires go where they have always gone.

I have only got 2 new wires and they go in the slots either side of the standard 7 pins.

One wire is white and one is light brown. Both are a slightly smaller dia than the standard wires for the 7 pins.

If the plug is not on then I have no lights. Put the two extra wires back in the extra pins and the lights come back on.

Thats why I keep mentioning the lights, because it appears they are affected by the 2 new wires and the sensor.

Perhaps we are talking about two different things?

Can you make your explaination a little clearer, and no I'm not trying to be funny, I have trouble marrying up what you are saying and what I am experiencing.

AnswerID: 479816

Follow Up By: Ross M - Friday, Mar 09, 2012 at 17:12

Friday, Mar 09, 2012 at 17:12
G'day Boo Boo
Is yours a genuine Dmax Towbar or one supplied by HR or other variety?
Under the back of your vehicle there should be two relays which click when you activate the central locking.
These swith on when ever there is a flasher signal come down either the Lh or Rh flasher. Both click when locking activated. It is the output of the relays which go to the Lh flasher, pin 1 and Rh flasher, pin 4 wires in the plug base on the tow bar.

If you have either of the mentioned side wires connected to the trailer electrics then something is wrong with your connections somewhere.
The two side wires, one goes to the earth wire of the plug base and the other end/side wire is designed to come from the black, to be earthed, wire of a reverse camera or sensor system.
So apart from the trailer system and the reverse sensor system having ot use the same earth wire in the plug base, this wire going to chassis earth, there should be no connection with the trailer wiring whatsoever.

Exactly which lights do you not have when the plug is in or out? Confused here.

From what I can work out regarding your lights the side wires are somehow connected to the trailer feed wires in the plug base.

As mentioned before, only one of the side wires is connected to earth, the common chassis earth and the other wire has nothing to do with trailer wiring.

Inside the plug base is a tiny reed switch which is designed only for very small milliamp flows. If somehow your supply or trailer earthing is going through this minute little switch it won't last long and the lights will again not work.
FollowupID: 755460

Follow Up By: Member - Boo Boo (NSW) - Tuesday, Mar 13, 2012 at 15:12

Tuesday, Mar 13, 2012 at 15:12
G'day Ross

Well it's finally making a bit of sense.

Yes it is a dmax plug, not an after market job.

I now understand what your saying.

Now for the lights confusion. When I take the socket that is wired to the car off the car I then loose the lights and indicators from the back of the car, not the trailer.

However, when I put the socket back on the wiring on the car everything on the back of the car works againwork again.

Communication is a wonderful thing. If we could get it right every time we could make billions teaching others how to do it. LOL

FollowupID: 755754

Follow Up By: Ross M - Tuesday, Mar 13, 2012 at 18:06

Tuesday, Mar 13, 2012 at 18:06
G'day Boo Boo
I don't want to repeat myself but it is important we are all talking the same thing.
I know you can handle this, just to be clear

The Brake signal goes to 6
The Park lights go to 7
Earth to 3

LH flasher from relay out 1
RH flasher from relay out 4

The others are electric brake and + trailer supply as you know.
The bit screwed to the towbar is the 7 pin socket
The bit on the trailer wire to connect to the vehicle is the plug.

If you unwire the socket from the vehicle but or unblot it from the vehcile then it seems the earth of all your rear lights is also earthing at the earth of the trailer plug. Interupt the trailer earth and you interupt the earth to these lights.

Who wired this thing? The earth of the vehicle lights should be autonomous and not dependent on the trailer plug in any way.

If the vehcile lights only work when the plug is in the socket and trailer is connected to the vehicle it would indicate the earth for the rear vehicle lights are earthing through the ball and there is no effective earth at the trailer base socket.
Check this out it's there somewhere.
I hope this makes sense. Yes teaching vehicle electrical is what I have done in the past.

Ross M
FollowupID: 755772

Follow Up By: Member - Boo Boo (NSW) - Sunday, Mar 18, 2012 at 18:23

Sunday, Mar 18, 2012 at 18:23
G'day Ross

Sorry about the delayed reply, but I have been getting a house ready for sale and the Dmax and caravan ready to go to St George Qld. We arrived today.

Ok I think I see the problem.

I had a look at my follow ups and see that I have mention the plug at one stage.

My problem was only with the socket screwed to the towbar. The trailer was never attached to the socket.

All the wiring to the socket (female) screwed to the car are in the right holes.
It was when I removed the socket from the car that I had no lights etc.

Anyway they are now working OK.

Thanks for your patience with me and the detailed explainations.

FollowupID: 756165

Follow Up By: Ross M - Sunday, Mar 18, 2012 at 21:59

Sunday, Mar 18, 2012 at 21:59
It is good you got it working but it does indicate the fact that the earth of the rear lights is dependent on the earth of the trailer 7 pin base instead of there being a definite original earth and an additional earth for the trailer base.

It would indicate the installer of the towbar doesn't really follow sound wiring practices.


Ross M
FollowupID: 756185

Follow Up By: Member - Boo Boo (NSW) - Sunday, Mar 18, 2012 at 22:22

Sunday, Mar 18, 2012 at 22:22
G'day Ross

Based on your last Post I am going to drop into a Dmax dealer when I get home.

FollowupID: 756188

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