Thread: L322 Trailer Light Electrics

G'day RM,

If you can't see a big old fashioned round 7 pin plug (usually toward the passenger side) when you look at the rear of the vehicle then it's possibly a good sign that the towing pack was never fitted.

Next thing is to open the cover over the rear fuse box (drivers side rear in the cargo area). There is an additional little box in there. Refer attached pic.

If it doesn't have this box of electronic wizardy then it's about $600 to obtain and fit. This device is so that the car computers know that there is a trailer attached and don't attempt to do silly things, like alter the height of the vehicle during travel, and other more mundane things.

HTH. Cheers,
Iain

Thank's RangieBit, there was no plug at the rear of the vehicle, and I don't recall seeing this little white box in with the fuse box... not that I knew what i was looking for in there anyway!

Where would you recommend getting it fitted? Presumably a dealer would be more costly than elsewhere...

Does your car have the tow pack electrics as pictured above? Mines got a flat 7 pin plug tucked right up under the car it took me 5 mins to work it out.

We had a pretty good look under the car and around the tow bar... and nothing was obvious, so pretty sure this little (fundamental) gadget wasn't fitted!

The tow bar receiver is part of the car - they all have it. The tow pack option was the electrics, there was one that I looked at that had the hitch and ball, but no electrics.

The small box in Iain's pic is what to visually check for. It's the Trailer Light Module, it's a plug in device so you could check the UK's many sites, even for a 2nd hand part. You need this unit, If you try and wire up trailer lights the old fashioned way (splice into the tail light harness) the LCM (Light Control Module) will sense the extra load and turn the circuit (you car's tail lights) off thinking there is a short... As Iain said the car also makes some electronic changes once a trailer is detected.

Once you have this installed, if you want to run trailer brakes or have LEDs on your trailer there is more todo.

Hi Harlie can you explain more about wireing up tralor brakes . I have a P3 that I have not fitted yet. Thanks in advance. I'm hopeless with electrics


Gary

Hey Gary.

There are two issues with electric brakes that the L322 share with D3, D4 and RRS, solving them is the same process but the bits are in different spots....

1st is the harness from the Trailer Light Module to the factory 7 pin plug under the bumper is not Aus standard - its EU and the colours are different not that it is the colours that are the problem but it adds to the confusion. Big problem here is that EU has 2 tail light circuits, pin 7 and pin 5. You need pin 5 for trailer brakes so the wire going to pin 5 (brown) has to be cut and joined to the wire going to pin 7 (Black), you need to join these to prevent getting a light out message every time you connect a trailer - the TLM checks both indicators, brake and tail lights in the L322. I did this about 100mm from the TLM. If the previous owner has towed the dealer may have already done this bit, or part of it (yes the dealers are cutting and soldering the factory harness, but only when fitting a controller or if the owner complains!) - first pull the socket off the car and check it matches the EU diagram below – giveaway is black in the middle instead of brown. This first bit is really important, in the D3/4 section there was a write up by a bloke in Melb who picked up a new van and towing it home the auto lights turned on resulting in van brakes locking up (auto elec who installed the controller didn't know about this 1st issue).

While you’re there cut the wire going to pin 2 – it has the rear fog lights and it’s caused many problems on here when a trailer is used with something connected to pin 2, I connected the reverse lights so the camper has reverse lights, handy when arriving at camp in the dark.


2nd is the connection of the “Brake light sense” wire (red) for your new controller. It must connect to the output of the LCM. Usually this connects to the brake light switch under the brake peddle, but in later euro cars the switches are Hall Effect meaning that they won’t be giving a 12v signal when on. So it needs to connect to the wire carrying the brake light signal to the TLM from the LCM (not the actual brake light). "Red brake switch sense wire connected to Black/Blue wire coming out of top connector of the Light Check Module (LCM)".

Take a look at: http://www.rangerovers.net/outfittin...kecontrol.html it details a LHD vehicle but the only difference is that you want the controller on the other side which makes it heaps easier, mine is recessed into the pocket where the OBD2 port is - just make sure you solder and don't use those stupid blue connectors like he has, they don't last...

The output from the brake controller (Blue wire) can then be connected to the (Brown) tail that was cut (going to pin 5) while solving the first problem. The result will be the brake controller feeding pin 5 and TLM feeding both tail light wires to pin 7.

The Aus standard is also in the attachment.

Hi Harlie

Thanks for that. Mine has a factory EU 7 pin Socket & an AU 7 pin socket bridged from the EU socket. So without checking that part may be O'k. Was there when I bought it. I have also fitted a 5 pin socket as well, bridged from the 7 pin. Like to have both 5 & 7 pin for different trailers, sometimes not mine.

Only need to sort out the brake controller. I think. May end up putting mine on top of the dash next to the A pillar. Looked at the little cubby but I not sure if unit will fit in there. What unit are you using.

Gary