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Heated Screen Problems


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Hi all

The windscreen on my 2015 Titanium Hatchback was replaced by Auto Glass in the summer due to a chip right in front of the driver.

The heating did seem to work on the new screen when turned on on the odd rainy day as you can see the area at the extreme edges that were not heated still misted up .

But now it seems to not be working as it wont clear even slight misting and or any frost even after the preset time it turn itself off. I sat in the car for 20 mins and no difference until it turned itself off.

The original Ford screen was very quick to clear but this new one doesn't seem to be doing anything anymore.

So i had Auto Glass back out yesterday to test the screen and possibly replace if faulty.

They tested the screen with some kind of meter and claim the screen is ok , so we tested the fuses for the screen which according to the manual are 61 and 66 @ 40amp.

Fuses were ok .... so we then gently laid the new screen on top and wired it up and it still wouldn't heat up. He used some kind of digital thermometer thing and it didn't register any temperature change.

Strangely when everything was disconnected from either screen if i pushed the front heated screen button it still lit up ?? Is that normal ??

So i have phoned Ford and it goes in next week ... they started to get a bit iffy on the phone when i said the screen had been replaced 6 months or so ago.  " Oh so its not the original screen blah blah etc etc"

The car is less than 3 years old so should be still under warranty shouldn't it ??

Auto Glass have said that if its something they have done that's caused this then they will obviously pay for repairs.

I can tell this is going to be a messy affair already though ......  

Any suggestions on what else to try before it goes in or any info that i can be pre-armed with for when the both start blaming each other on where i stand  ?


Thank You

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I think what it comes down to is:  is there voltage and the capability to supply a high current (amps) at the connectors. If not then there is a fault with the electrics and not the screen and it is extremely unlikely that replacing the screen could have had a detrimental effect with that. So if the fault is with the electrics then I think it would be totally unreasonable to argue that a screen replacement was a reason to refuse warranty repair by Ford.

Because the screen uses tons of current it uses a relay or relays (some have a separate relay for left and right sides - I do not know if yours does or not) and the power at the dash switch is being used to signal those relays not power the screen directly so I suspect the light just means it is sending a signal to the relays and any fault with the relays and screen power directly do not affect the light. 

you can tell if a front screen is drawing power or not by- start engine ,let engine tickover (when warm) turn on all lights- as many as possible, turn on heater fan and heated rear screen. Now turn on the front screen and the  engine note/speed  will change momentarily and the lights dim momentarily as the huge power consumption of the front screen kicks in

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That's good information ... I'm not sure where the relay is if there is one but I'm hoping its going to be an easy fix.

It doesn't go in till next Friday ... I'll do a bit of googling to see if i can find out about relays .



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I assume there was as he tested the connections at the bottom of the screen and I'm sure there as power ... or at least his little test meter beeped which he said if it beeps means its working.

I cant find any info about the relay ( if there is one ) at the moment .... i did look on google earlier but I'm afraid vodka has stolen my attention :wink3:

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as i said the relays are non servicable, the relays provide the power to the fuses . so if you have power at fuses then the relays are being powered up via the front control module. that leaves the connnectors to the screen and earth connectors from screen. its a very simple circuit.

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I think Auto Glass must have a faulty batch of windscreens as my neighbour as had his windscreen replaced as his heated windscreen would not work last week. He called Auto Glass and it was replaced under warranty as he only had it fitted June 2017.

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I had one replaced on my previous Fiesta (due to large crack) and after a few months the left side was taking a lot longer to clear than the right and then the left stopped working altogther. I ought to have got the windscreen company (can't remember which one ) to have a look but never got round to it before selling car.

The left and right are separate circuits in case anyone wondered.  I checked the voltage and there was voltage there. As the left side failed gradually it makes me think there was some problem whereby the volts could get through but when there was a huge power demand there may have been a lot of resistance on a bad connection?  The screen connector has spade connector fixed to the copper strip in a lump of plastic, I do not know how it is fixed on, but I would have thought if that connection was poor then it would get hot and melt the plastic. But if there is a poorly soldered connection in the main fuse/relay box perhaps something like that could cause it?    I recall Mk5 Escorts had a common problem with the fuse/relay boxes having poor soldering in them.(I had one where this affected the ignition circuit, heater fan and dip headlights and another where it affected the ignition circuit and heater fan - on both, the solution was to rewire those circuits bypassing the faulty bit, relatively easy on cars of that age - not so easy now)

Anyway, I am not sure checking the voltage at the connector is good enough as a voltmeter tests it with no load whereas the heated screen uses loads of power (the only thing that uses more is the starter motor).

I also have a friend with a 2005 fiesta where the screen does not work. I have checked the voltage is there on both sides(it is) but screen does not work, There is continuity between the positive and negative on each side of the screen. So again I can only think it is an electrical problem where it can't get the adequate amps through. 

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  • 2 months later...
17 hours ago, Niall Houghton said:

My front windscreen only clears on the passenger side, I'm just going to rely on the fan, rather than getting it fixed.

My wife's MK2.5 Focus also does the same, as it happens I had the scuttle panel off today to check if the cable on the driver's side had been damaged, but it hadn't so no joy there!

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  • 3 years later...

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