So after doing my fun/awesome LR4 nav display install I end up with a hard fault with the front left corner valve. Of course this fault really just means the front valve block. Coincidence? I mean I was messing with a ton of stuff. Nope, it was a faulty wire in the harness.

So after reading that there is a sorta known issue with a harness rubbing on the frame "horn" thing on the driver side (LHD) I decided to look there. The horn is the metal thing attached to the frame behind each front wheel. Its secured with three 15mm bolts with captive j-nuts on the frame. There is also a hook so you have to lift up before you lift away. I think in 2007 these were welded on though. Anyway, removal is not hard and it makes inspection much easier. For me though I could find no issue there. After tracing the harness as best I could I found nothing visually that indicated an issue. Thought I may very well have to replace the valve block.

But I decided to use my voltage meter to check for resistance across each wire. I mean I had it all part and could test each wire from end to end. I no nothing about ohm and stuff, at least when it comes to this so I just tossed my meter to 20k setting. Then on the valve block end I jumped two of the six wires. On the other end I had the middle connector disconnected from its other half and metered across the two wires I jumped. I had a reading of 15.something. Odd I though cause I would expect either open (which is what the meter display when the probes are on nothing) or 0.00 ohms meaning there is NO resistance. There should be none in theory. So I tried another pair. 0.00 ohm. Ah! Went back and played with a couple combinations that ruled it to bed the black wire with yellow stripe. Also while there are six wires, I only tested the four found in the connector, I never did look for where the other two ran off too.

Anyway the next approach was to re-inspect that specific wire. Still found nothing visually even though I suspected this wire was at fault. But I could not really get a good look along the underside of the radiator where the harness runs. So I needed to simply replace the entire wire. First I made a splice just behind the water tank (red circle). From here to the connector I metered and got 0.00 so I knew form here to the connector was fine. So I spliced in a new wire here running it tight under the radiator along with the original harness and air lines. At the other end I cut at the connector a couple inches up. If you pull the lower part of the fender liner you can pull the connector towards the forward skid plate and work on it under the bumper with plenty of room. When cut I again tested the short wire to itself in the connect. Tested 0.00 so that told me it was not an issue inside the connector itself on the valve block end. So I soldered in my wire and buttoned things up and all was well.

So this was a very odd issue and normally I would have tossed in a new valve block had it not been for the forums. And while my issue was not exactly the "common" wear point problem it was still a wiring issue. Hope this helps someone else at some point.

* In the first pic is the typical area where the harness wears onto the metal horn thing, which I have removed. The area circled is where it happens. While I pulled some cable wrap back most of these wires are totally exposed. This is the middle connector. The valve block wires are along the arrow train then loop around back to the middle connector. For testing you will be doing so with the connector the is lower in the pic. The other end goes into the cabin. The blue connector that is mostly hidden is the power connector for the air compressor. It has a couple other wires too. You can again see how the wires are exposed and can actually rub on the body. When I closed things up I covered it with wire wrap. If you do not have rear AC you will not have the annoying AC lines in the way. There is a 10mm bold on the underside you can remove to slightly lower the lines and get more room.

* Second pics it the forward part of the wheel well. Red circle is where I made my splice to start the new line.