Land Rover discovery 2 td5 three amigos

[Cynic]

my 2003 td5 discovery 2 has developed the three amigos problem.  I've been through the various chief culprits as expounded on you tube and landy groups i.e. wheel sensors, shuttle valve switch, shuttle valve switch internal connector plug bypass without success. Having interrogated the abs with a plug in diagnostic box it tells me there is a reference earth fault.  I googled the 3 amigos and whilst the landygroups mention it bitterly no one seems to have gone deeper than sensors or switch connections.  I'm hoping someone here has had the same problem and can suggest where the earth reference point would be connected before I make a journey to the local reference library in the hope they have a detailed service manual. 

[The Natural Philosopher]

Brake switch?

[Cynic]

Interesting thought but I think the brake switch might only operate the brake lights. Trouble with my particular model it's got too many complications for what should be a workhorse. From what I've gleaned so far the abs valve block contains two microswitches in series which operate when fluid pressure is applied. The two n.o. switches have internal shunt resistors so no pressure yields 4k ohms, one or both switches operating yields 2 or 1 k and this is connected to a unit hidden within the car that also reads wheel rotation speed and calculates which brake cylinder to preferentially apply fluid pressure to. The reference earth I'm guessing relates to the state of the valve block pressure switches but how it measures seems to be the crux of the matter.

[The Natural Philosopher]

Not on freelander., Another terminal that cancels cruise control and I think switches on ABS

Very easy to renove and test.

And very cheap to replace.

Trouble with my particular model it's got too many

[newshound]

I've never looked for Landies, but eBay is a good source of pirated full service manuals on CD, for a pretty nominal price.

[Dave Liquorice]

operate

We is talking Disco II not Freelander...

Having said that, from memory of owning two Disco II's I don't think any of the switches directly control the device/system they are related to. They all go through "computer" somewhere which then controls the device/system according to its programing and other inputs.

Not quite sure what the "three amigoes" are. Is that when the traction control, ABS and diff lock light all come on? Check the diff lock switch (and connections) on the transfer box. For obvious reasons the traction control/ABS computer throws a hissy fit if it thinks the diff lock is engaged.

Yes, some Disco II's had transfer boxes with a center diff lock in the transfer box. You could crawl underneath with a 10 mm spanner and engage it if you wanted to...

[Cynic]

No diff lock on this model. The three amigos are hill descent, traction control and abs lights. Since posting I've been advised the abs ecu is located behind the passenger side dash panel and there's an earth point located near it. Seems I've got some gymnastics to encounter to access the unit. I wish I was as flexible as I was twenty years ago.

[Dave Liquorice]

Maybe not on the transfer box Hi/Lo shift lever but the gubbins can still be in the transfer box and the diff lock switch.

I had that a couple of times but I have a feeling it was knackered wheel sensors, so new hub time. B-(