Heated windshields

Thanks guys, I will check the fuse. Question: how do I test that it's operating correctly? It's 70 degrees in San Diego, not much opportunity to visually check to see if the window is defrosting !!!

morning dew?

yeah, that was my best guess. leave the car outside tonight, and early morning give it a whirl...

FYI, this SSM was just turned into a Service Action bulletin for MY2012-13 LR4s (and RRS.) The repair will be performed automatically upon your next dealer visit for regular service, no need to request it, if your VIN is among the affected range. Kinda like a recall, but without the urgency.

This forum won't allow uploads of PDFs except tiny ones, but the link below should work if you need a copy of the Service Action.

https://app.box.com/rrs/1/651893025/16311514903/1

Thanks umbertob. I had a bad battery and brought the truck in on Tuesday, they were aware of the SA bulletin and are doing the "recall" on the fuse as we speak
I knew about it last January, but SoCal weather didn't really give me a reason to get on it

Recently had 2011 LR4 HSE-Lucx windshield replaced, and Safelite put in an aftermarket windshield. I protested a little, but they assured me it would be OK. As soon as frost season came it was clear that the right side windshield heater was not working. Checked fuses, and sure enough right fuse was blown. Replaced it, and it promptly blew again. Using a DC clamp ammeter, I pulled the A pillar covers and started probing. Right side was pulling 40A (for a few minutes before blowing the fuse) while left side was pulling 37A. If I had searched the forum and found the TSB replacing fuse to 40A I would probably have done that...but instead I went back to Safelite and they agreed to swap the windshield for an OEM.

After swapping in the OEM windshield the left side pulls 28A and the right side 29A. So FWIW, the aftermarket windshield had ~0.35 ohm resistance while OEM has ~0.48 ohms.

For reference, when heater is on I measured about 0.2V to ground simply due to wire resistance. This doesn't concern me, but may be helpful to someone.

A few people have asked how to check whether or not the heater is working. Obviously one way would be a FLIR or similar IR camera. How I checked is simply pulling the A pillar and probing with a multimeter. The plastic cover labeled "airbag" easily pulls away revealing a T30 screw. With this screw out, the whole cover easily pulls away. Once the A pillar cover is removed, ribbon cables from the windshield indicate the heater connections. If the heater is working than 12..14VDC (depending on engine speed etc) should be on the hot side and ~0.2VDC on the ground (black) side. If voltage is missing, then suspect fuse.

Most multimeters are limited to 10A, so measuring current probably requires a clamp meter. Fortunately they aren't too expensive. I don't use mine very often, but really appreciate it when I use it (such as for this project). If you're making it this far into diagnostics, your kit should include a clamp meter.

A few people have suggested ground problems. If indeed there were a ground problem that would be indicated by high voltage on the ground side of the circuit (measuring anything much more than 0.2V on the ground side would make me suspicious). If you have at least 25A and low voltage on the ground (black) wire, then current is making it to ground so the circuit must be OK.

I put up with the strange visual effects of the wired windshield (stock and aftermarket) up here in the frozen north where frost is around Sept-June but if I lived somewhere like San Diego it would be a non heated all the way.

Many years ago my father owned an autobody shop in Montana, we would frequently replace broken, chipped or inoperable heated windshields in some of the higher end vehicles. At that time it was fairly new tech and was usually a very expensive option on a vehicle. We always used to laugh and say to each other how silly we thought it was that someone would feel the need for a heated windshield. Years later my Lr4 is the first vehicle that I have personally owned that has had a heated windshield, and I can honestly say that I totally understand the reason that people pay for the option. I live in Washington state and it frosts here fairly frequently. If your Rover sits in a garage, under a carport or in weather that is not below freezing then it is probably more of just a novelty than a necessity. Mine seems to work pretty quickly. Get in, hit the start button and it automatically comes on when its freezing. Hit the heated seat and steering wheel buttons, situate my coffee, select appropriate music, throw on my seat belt and by that time usually I can hit my wipers and the frost is no more. Sure beats ice scraper duty.

This vehicle is the first I've owned with a heated windshield, and I love the feature. What I don't like is the lights dimming briefly when it turns on, while driving. If it's cold enough, it does this on its own, regardless if the button is pressed or not. Anyone know a fix for this? After researching it, i'm pretty sure it's the front heater making the lights dim.

I love a heated windshield for the simple reason that I don't need to have hot air blasting on my windshield to keep it clear when I don't feel like having hot air blasting in my car.