MY13 Discovery 4 Electric Trailer Brake Wiring

Hi Pete,
Unfortunately it is not that simple.
The circuit as I have it will work correctly. The difference is that the diode will block or prevent any feed back from the P3 to the rest of the system but sill operate anything upstream of the diode including the brake lights on the trailer or brake controller. This setup will operate the trailer brake lights when the manual switch on P3 is operated but does not prevent the lights from working via the in feed (factory wiring).
The issue I have is that I am not getting any voltage on the anode of the diode (factory wiring) thus not operaterating anything beyond.
Cheers
Keith

Hi Keith,
Having another look at the diode which is correct, i took the cable running the wrong way around.
What you have done is correct.

All i can suggest is checking fuses & making sure the connection to the red brake wire is secure.
Fuse 14 behind the lower glovebox from memory, (mine anyway 10MY)
also be sure that you check them all (trailer fuses) as there are seperate circuits for just the trailer, your HB will detail all the fuses.

HTH Cheers.

Have you checked the voltage before the connector on the fuse side/ factory side of the connection. Could be a bad join.

Hi,
Do you have constant power hooked up to pin 2 the reverse pin? With hydraulic/electric brakes generally your unit on the trailer has an led light on it, this will light up when you do the above and you are then good to go.
What sort of brake system do you have on the trailer?

It would appear that I have been outsmarted by a car!
It seems that the computer in the D4 shuts down several light circuits after a time whenever the driver's door is left open - brake lights being one of them.
I am yet to figure out what combination of open doors etc shuts down what but suffice to say I have learnt about the trailer brakes.
So at the end of the weekend of checking and double checking I had, purely by chance, my lights back and all working as they should without any physical changes.
Cheers and thanks to all for your input.:)

I am not sure about the diode installation. Does the P3 red brake sense wire supply current that would activate the car's brake light circuits if a diode was not installed? Having just posted tonight about issues I had with an auto sparkie installation stuff up titled "auto sparky woes and errors" my fix did not include a diode in the brake sense red wire and I have not come across any issues as yet with my installation of the Prodigy P3 into the D4's trailer wiring loom.

I have included photo before and after fix. I still don't know what the blue wire in the trailer loom is used for. ? where comes from or goes to.

I am attaching photo of my set up - there are 2orange wires in it that are patches/repairs to the original brown and blues wires cut by the auto sparky that I had to reconnect. My heavy red wire is an extension to the P3 red wire, and heavy black wire attached to cut brown wire is the P3 blue wire extension. The sparky cut the brown before the black wire came off, and he fed the P3 blue to the brake loom red wire, and the P3 red wire to the loom's brown wire. No wonder nothing worked - no trailer tail light and Pin5 "funny".
http://www.aulro.com/afvb/attachment...1&d=1368969338

I would appreciate sniegy's comments

Rosco

I fit the diode to all vehicles.

It is there to specifically protect the CJB from feedback. It only costs a dollar at most, so cheap insurance. The stripped end or Kathode needs to go towards the brake controller.

Cheers

Hi,
I am new to this site but found the information already very helpful.
I have a MY13 Discovery 4 TDV6 and I need to have a brake controller fitted for a Jayco Caravan.
I have been quoted $1200 for supply and install a Tekonsha Prodigy as well as an Anderson plug.
Does this sound reasonable for the work involved.??

Quote:

---

Originally Posted by Wayb4u

Hi, I am new to this site but found the information already very helpful. I have a MY13 Discovery 4 TDV6 and I need to have a brake controller fitted for a Jayco Caravan. I have been quoted $1200 for supply and install a Tekonsha Prodigy as well as an Anderson plug. Does this sound reasonable for the work involved.??

---

Excessive. $160-$200 for the Tekonsha.
Fleecing and gouging.....
Brett.....

Google for the p3 available from ebay - note the requirement for the p3 to be installed horizontal when looking at the front - and there may not be enough room near your knee due to airbag so you end up with it on the dash somewhere

You should be able to negotiate a better install price from LR dealers. New car I would use LR dealer or authorised service who are experienced.