I was lucky. In a moment of inspiration, I ordered it and it miraculously arrived per order. So, I don't have your challenges, but here's how I would start to solve them. YMMV. PowerfulUk has a take off loom that fits the tow bar connector. I would buy this loom, splice in my own trailer harness to see if it lit up correctly and then call it a day. Obviously power is going to it or the loom would be valueless. For a nice "OEM quality" (Goonzquad quote), I'd try to connect to the loom a female connector somewhere on the outside so that I could just plug in whatever 5/7 pin that worked. Good luck!

PowerfulUk Link.

 

Thanks for the great idea!! I just contacted PowerfulUK and asked them if they could make a brand new trailer connection loom that would just plug into the tow bar connection. If not I will go with your idea and connect a new 4 pin female trailer connector.

 

Hi guys,

thanks for all the tips. I also installed it myself on my 90S and had a few steps missing for my model but managed. Also took it to the dealership for programming the module.

Only issue I have is I want to test it actually works and bought a 4 point connector tester at home depot and the lights don’t do anything.

how did you confirm the wiring was working? Through the 4 pin connector or 7 pin round connector?

 

@l_adrianza In my case, I hooked it up to my utility trailer and "did it live" to see that it works. I've not used a tester myself, so unfortunately I can't offer any advice there. Perhaps if you went to your local UHaul they might let you hook up to one of theirs to see if it is an actual problem, or some kind of issue with Defender+Tester?

Nice looking rig, btw! The 90's look like loads of fun. You mentioned some steps that were missing for the 90 -- if you have notes from your install, I'd love to update the original post.

 

@l_adrianza - Before I started to disassemble all that and check things, I would suggest doing two things first. 1) Get another tester. Hate to say it, but some testers are faulty. Or, check it on a different vehicle to make sure it works. If it does, double check that it's fully seated. 2) Check the grounding on your harness. That is the #1 thing that makes trailer wiring go wonky. It's almost always the ground. Many/most lights and other miscellaneous electrical items will ground straight to the frame without a dedicated wire and it almost always goes fritz.

If you do disassemble it to dive back in, I'm sure that you learned an important lesson here: Always check the electrical connections before putting all the bits and parts & trim back onto it. I'm not goofing on you, it's just one of those things I've learned to do thru the same hard experience you are having. Hopefully the two of us can convince some other poor schmoe with our tuition payments. I hope it's the first two, but if not - post the "rest of the story".

EDIT: Just zoomed into your pics. Looks like you have both the 4 & 7 pin connectors on there. But I don't see any wires off the back of the 4 like I would expect. Maybe they are coming in laterally from the 7. I would check the 7 pin as well in the hopes that the 4 may have a connection problem or be "deleted". So make sure you check both connectors. If you have a trailer, you're going to want to use one of these ( ). I know you have both the 7 & 4 pin connectors, but I think I have one of these in each of my trucks. Never know when they come in handy. You can get one of these likely cheaper than a 7 pin tester (if you've proven the 4 tester works on another vehicle). Also, if there's not a U-Haul nearby (or they won't let you test it), you can always go to a Lowes or Home Depot. Most of them around us have trailers locked up in the parking lot. Just pull up to one and connect the connector. Test the lights. I recommend asking some guy getting carts first, but I'm sure no one will care as long as you don't try to make off with the trailer!

 

Thanks! Sorry for the delay, main steps missing for a 90S per my experience:
1) Really re-think not paying the dealership, its a lot of work
2) pre test electrical functionality of all parts prior to installation
3) the instructions/diagrams for installing the wiring harness for the 90S are missing, so I had to improvise:

1. Used gorilla double sided tape to secure the electrical module.
2. Make sure you ground to the right type of screw! they are coated in white/grayish special paint!
3. In order to ground in the 90S, I had to remove a unit to uncover the right screws

4) Test electrical post installation with a circuit tester, I can confirm both the 4 & 7 pin have electricity running through. I couldn't get 2 home depot light testers to work

Hope this helps others with Defender 90's!

 

Can't agree more with your advice, pre-test everything before taking out the first screw!

1. OMG, thanks for the grounding tip! I had grounded the wiring harness incorrectly, I thought any screw would do, turns out I was wrong and needed to ground to the specially coated/designated screws for grounding which were hidden behind an electrical unit on the 90S...
2. I tested with an electrical circuit tester and confirmed there is electricity going through for blinker lights (both sides) on both the 4 pin and 7 pin connectors. Still not sure why the home depot testers don't work...
3. When I click on the interface of the touchscreen to add a trailer, and plug in the testers it still doesn't seem to recognize anything is plugged in... not sure if I paid LR dealer for nothing....Do you have experience with the interface?

 

If still having issues, you are beyond my lowly skills. You should PM @Mark1107 . He's the genius with those types of interface things. Or maybe @sarek. I'm sure that either of them could turn the Defender into a Transformer, given enough time.

 

That makes total sense that grounding was the issue, and yeah, there were a few different places in that area that probably would have seemed like they worked.

Regarding the test results, IMO if you're getting voltage when you turn on the blinkers, then most likely you're good to go with respect to the harness working correctly with a trailer. I have no clue why the home depot tester wouldn't work, except to say that because the LR does seem to be able to detect the presence of a trailer in order to activate functionality like the trailer specific camera view... because of that, I imagine they might be doing something with those wires that the tester isn't expecting. For example, they might be looking for a specific level of resistance or amperage between the ground and the trailer running lights (the kind you'd see with an actual trailer) before fully "activating" the harness wiring. The home depot tester was likely designed for towing systems that are less sophisticated. Sort of a hand wavy theory, but this is all to say that I would recommend trusting your volt meter over the tester.

See above. I would bet that the tester isn't enough of a load by itself to activate the towing specific features. Here's what I've noticed:

• If you haven't had the dealership program the ECU, you won't see a Towing icon in the list of apps on the home screen.
• Once the dealership programs your ECU, you'll see a towing icon that allows you to open up the towing screen and add your trailer(s). When I first started towing with the Defender, I got a tape measure out and measured the trailer so I could enter all the values they ask for (wheel width, and distance from axle to tongue). This is to activate the visual guidance (curvy path lines) when you're in the towing camera view. If you have the advanced tow package, I believe you get some backup assistance -- but I don't have the advanced tow package, so I can't provide reliable info on that. I didn't find the visual guidance to be very useful myself, but the tow camera view was SUPER useful to be able to easily see where the wheels of the trailer are in relation to the lane/road.
• You won't see any other trailering features in Pivi until the trailer is actually connected. Then you should see a towing icon on the right side of your main Pivi screen (where the parking camera button is). I've actually got to tow my trailer this afternoon or tomorrow, so I'll try to remember to take pictures of the screens and post them here.

 

Here are photos of all of the software changes that I notice when towing.


Towing and Trailers menu in app list.

Home screen with trailer icon visible on the right.

Icons take you to the trailer menu.

Towing option for camera screen. Tapping either of the white arrows in the rear-facing view enables the side mirror cameras to monitor wheel position in lane.


Second camera view option.


Green trailer icon on right side of dash blinks when you use the blinker.


Alert every time you start the car with a trailer connected letting you know that you're on your own avoiding running into stuff when backing up.