LR3 tow wiring harness

[bbyer]

Trailer wiring info specific to LR3

The link below is to a number of files re the LR3 trailer wiring including the model number of the Ford adapter cable required to plug in under the front dash above the brake pedal for the trailer brakes.

http://www.bit.ly/13Dysjp

 

[cannonball55]

Thank you! I remembered seeing that but couldn't find it when I went searching. Thank you bbyer!

And thank you bump daddy!


Sent from Tapatalk using my iPhone.

 

[wheeler]

Which connection disables the rear park sensors?

I've recently purchased the LR4 hitch and tow wiring harness to add to my LR3 vehicle. I'm going to use the receiver hitch mostly for carrying bicycles on my Küat NV rack. The owner's manual states (page 153) that the rear park sensors are disabled when "a trailer is attached to the vehicle."

I've already installed the hitch and I'm considering whether or not to install the wiring harness as well.

I think my preference would be to leave the LR4 hitch in place on the vehicle continuously and just remove the Küat bike rack when I don't need it. I realize the loaded or unloaded bike rack would probably set off the rear park sensors.

My question is, what is the trigger that tells the vehicle that a trailer "is attached?" The presence of an empty hitch receiver? Or an electrical connection to the trailer tow wiring harness?

For example: if after installing the wire harness, every time the tow hitch is installed, even if nothing is attached to the hitch receiver, and the rear backup sensors are disabled... that wouldn't be good for me. Trying to decide if there's an argument for NOT installing the tow wiring harness until a time I truly intend to tow trailers, etc. Thanks!

 

[bbyer]

When the trailer is attached!

I think I detect a problem.

If I understand correctly, both the 3 and 4 detect a trailer when the trailer wiring is plugged into the vehicle wiring.

To be more precise, the vehicle detects the existence of non LED trailer signal lights. While I am not certain with the 4, (I do not think LR corrected the problem), regarding the 3, I say non LED trailer signal light bulbs as LED's tend to have so little current draw that the vehicles computers cannot sense the LED "filaments within" and hence assume nothing is connected.

Given that you have a hitch carrier with no signal lights etc, I think you have a problem, or more correctly, you would have to manually turn off the rear sensors from the dash button or build a version of trailer signal lights to create a load.

I guess it is time for someone who actually has a carrier to chime in as to if there is a problem.

Incidentally I assume the harness you purchase is pretty much official Land Rover? I do not think there is anything really special buried within the LR wiring harness but one never knows and messing up the electrical in a 3 or 4 can result in untold challenges.

 

[wheeler]

You're absolutely correct, bbyer. I do have a problem! I've had my LR3 for two months now and from the day it arrived it has had a park sensor fault. Every time you put it in reverse, the alarm goes off and the dash light blinks. And this is before adding the hitch or a bike rack. With nothing behind the vehicle the alarm goes off reliably every time you put it in reverse.

(Except for the day I had the tires replaced. When I picked up the vehicle after four tires were changed, the back up system functioned absolutely perfectly for twenty-four hours, then it went back to fault every time you put it in reverse. But all this is food for a separate thread.)

I scanned for faults and came up with two defective rear park sensors. I'm taking the vehicle in tomorrow to have the park sensors replaced, we'll see if that rectifies the park sensor problem. Yes, I do have the LR factory tow wiring harness and I was trying to decide whether to have the guys install the harness at the same time they're working on the back bumper.

I was just trying to pinpoint the deciding factor that disables the rear park sensors for towing, in case this could work for me instead of against me with a bike rack. Thanks!

 

[bbyer]

rattle some of the parking harness wiring

Dirty parking sensor faces will set off the alarm but I assume yours are clean. One of the problems with the front ones is bugs smash into them.

The tyre removal comment suggests to me a harness problem and the guys jostled one of the cables when removing the tyres.

Did they fool around with the spare tyre at all?

My guess will be that replacing the sensors will not resolve the problem, or it might, but that is because the problem was connector related rather than sensor related.

 

[wheeler]

Astute and helpful insights as always, Bruce, thank you. Yes, the tire shop pulled the spare tire down to replace it and when the parking sensor system started working I also imagined this had something to do with the wiring harness or connectors/connections. I will remind the mechanic shop about this pattern tomorrow when I drop off the vehicle. If I learn anything particularly helpful moving forward, I'll create a new thread but link to it here as well.

 

[bbyer]

Bridgestone H/L tyres

Yes, please keep us informed. I view is that whatever problem another owner is having means my day is coming as well.

I see you are running the same Bridgestone H/L tyres as I am. I regard them as good value for the money. So far, I seem to be able to stay on the road and that is why I purchased my 3, to remain between the ditches; exploring them is not for me.