The right side (all directions as if you are sitting in the car) of my LR3 windshield would not heat from the day I bought it. It kept blowing the fuse every time I would try a new one. After fixing a couple of other things I thought I would dive into this issue. I checked the windshield out and no issues with it.

After a lot of troubleshooting I ran a new power wire (with fuse of course) straight from the battery outside the car and into the hot on the windshield. This seemed to work great. I assume there is a short somewhere I cannot get to in the power side from the fuse in the engine bay to the wire on the windshield.

Does anyone know the best way to get a new wire from the battery fuse box in the engine compartment through the firewall into the right A-Pillar? I removed a lot of trim and looked everywhere but I cannot seem to find the penetrations in the firewall on the right side. I am guessing they are hidden well behind the battery somewhere.

Worst case I can run something to the left side, through the steering column grommet, across the car and up the A-Pillar. If there is an easier way I would definitely prefer something else.

Thanks

 

Rather than the steering wheel grommet which works on a Chev but not so certain it works on a LR, there is the clutch rod hole that is filled with a rubber plug on the automatic transmission vehicles.

Others will explain better than I, but behind the brake fluid reservoir on the steering wheel left side, looking from the engine side, one can sort of see a rubber plug about a half inch in diameter on the firewall.

You pierce the plug and then push a wire thru there.

If you do not have the heated windscreen wiring diagram, below should be a link to a single page wiring pdf even if it appears to be a wheel pdf link - do not know why it shows that way.

I assume that you have looked but my guess would be the short would be near where the windshield connectors are attached - the hot grounding to the A pillar; perhaps a conductor got pinched or pierced during a windscreen change. An ohm meter should show the hot is grounded but I guess you already know that.

Also I assume you took your test power from fuse 15E, the right hand power circuit? I ask as maybe there is a problem right in the fuse area, very unlikely but .... Also with an ohm meter, you should beable to test the PS wire and prove that it is shorted to ground, or perhaps you have.

DISCO3.CO.UK Photo Gallery - LR3 miscellaneous/LR3 Silver 10 spoke grooved wheel Cromodora of Italy 18 inch x 8 ALY72201U85

http://www.disco3.co.uk/gallery/albu...en_page_60.pdf

 

I will have to go find the clutch rod hole. That will probably be best for passing through that side. Thanks for the suggestion!

The wiring diagram is helpful. Are there any files in the manual (I have the pdf's) that show actual wiring harness routing behind the dash? I am curious to see where the wires go.

I do think its somewhere right at the top near the connections because when I put the A-pillar trim piece back on I think something is getting pinched and shorted. It seems to work with the trim piece off, and the wire reads ok from the fuse to the windhsield connector with the trim off. I cannot find any sign of shorting though on the wires that I can see.

I did take test power from 15E. The fuse area is scorched (was like that when I got it) but I assumed this wasnt causing the issues since I can get it the work fine intermittantly. Who knows though.

I will check in there more closely tonight. I did see on the carfax that the windshield had been replaced. I am assuming from rock damage. Maybe something got pinched during the install, but it is pretty hard to tell since so much of the wiring is covered by the dash.

Thanks

 

I do not have anything re cable routing however the attached shows the grey coloured connector C2409 / C2410 location. I do not know if the picture is for LHD or RHD but my guess is the connector is located on the drivers side kick; ie my guess is that the cables come thru the firewall high up either behind the battery or it may be they go thru on the steering wheel side as there is a real bundle of conductors crossing in the cowl area. Regardless, once thru, some conductors turn upwards or sideways and some downwards under the kick panel of both the driver and the passengers side.

The conductor you will be looking for is the PS wire. I think it will be a purple conductor with a grey stripe but may be the reverse of that. U is blue for what it is worth.

Once you find the 4 pin grey connector, (it will be there somewhere), then hopefully the PS conductor is OK between the fuse box and connector C2410-3; if so, then you may only have to run new conductor between pin 3 of C2409 and up to the windscreen; in this case only maybe 3 feet or so.

You may have a conductor that is internally broken but the insulation is for the most part intact and hence one cannot see the break. This would be squashed somewhat behind the windscreen glass. It is a good sign that the short tends to show up when the A pillar interior moulding goes back on. If I recall correctly, there is one screw behind that airbag plastic cap - maybe that is causing the short - the screw threads pierce the PS conductor.

 

FWIW, my right side windscreen heater was also not working. I pulled the A-pillar cover and took a look, disconnected and reconnected, then checked fuses and reset relay a few weeks back. All for nothing...next cold snap with iced windscreen and only the left continued to work.

This evening in preparation for possible icing tomorrow morning, I pulled the cover once again and check for continuity at the window...good. Checked for continuity from the ground wire to ground...good. Started vehicle, turned on windscreen heater and checked for voltage...nada...back under hood.

Checked both fuses again, checked with VOM to make darn sure...both checked out good. Pulled relay and swapped it with the relay for the air compressor. Decided that was about all I could do...or was wiling to do at the time.

Back into vehicle, started vehicle and activated the windscreen heater...checking for voltage on the positive wire. Presto! Voltage! So I thanked my lucky stars and buttoned it back up...I love it when I fix a problem and without breaking something else or really knowing what I did. I guess we'll see if it works tomorrow morning.

 

If tomorrow, the windscreen does not function, perhaps remove the A pillar covering and leave it off. Maybe it, or the screw is pinching the conductor and a short results.

Switching the relay should not have done anything as one side worked unless the relay is bad but then both sides should quit. I am starting to get suspicious of LR relays however. It seems a fix for a heater fan working but acting up can be just to install a new relay.

The relay appears OK but is not; same with the air compressor relay. For an unexplained reason, for awhile with every new air compressor, LR said one was supposed to install a new relay.

Please keep us informed as to how the windscreen heat fix works, or not.

 

I took another look at it last night. Checked very thoroughly for anything that could be pinching or shorting the power when the A pillar was on. I noticed a few sharp raised areas on metal portion of the pillar under the hot wire that could be penetrating, but it would be pretty unlikely. I covered everything with a few layers of electrical tape just in case.

I also rechecked continuity to the hot and ground wires. The hot checked out perfect no matter what after that. A pillar on and off. The ground however was giving some inconsistent readings.

I ended up running a new ground, down the side because it was easy. I blew all my fuses so I will get some more and check it today.

I guess if all else fails I could replace the relay. I am not sure how that could be causing a problem though since both the left and right side come off of the same relay post.

 

It sounds to me like you are making progress.

Re the relay, I figure you could switch R9 with R7, the 70 amp air suspension relay just to try things out.

Also if you are purchasing a relay, you should get the new grey coloured cover relay for R7, the air compressor, particularily if you do not have the new one. Apparently the factory original old style, (black plastic cover), gets weak with time. The part number is YWB500220. Since both R7 and R9 relays are the same, probably the windscreen relay is not the best either if used alot.

DISCO3.CO.UK Photo Gallery - LR3 Air Suspension fuse 35P ECU Manual Shut Off Switch/Underhood Fuse and Relay Box drawing


Relay To Amp EAS Pump (Genuine Part # YWB500220) - Land Rover connector\relays\flasher from Atlantic British

 

I have a windshield issue where several strips do not appear to be working...but I have a feeling that this is indicative of a failure of particular elements, not with relays or wiring...

 

I saw some posts like that when I was doing my initial research before diving into my issue.

I guess I am kind of baffled as to how one side could partially work. I believe the heating element is just like a big resistor embedded in between the layers of the windshield glass. However, I am pretty sure if any of the wires are broken an open circuit would be created. So how could it be partially functional?

Perhaps the design is more complicated than I thought. I am not an expert in electrical engineering though.

I would love to hear more about how this system is designed if anyone is an expert. I read through all of the documentation included in the workshop manual, but am still baffled.