V70: Electrical Heated Windscreen Retrofit

[Clan]

Originally Posted by JES

It is interesting to think about what optional component wiring would and wouldn't be included in a standard harness, unless there is a dedicated control module for the windscreen then a re-flash of existing modules must be possible. However it seems that this is not a system that's often explored.



I would also agree with Tannaton that a diesel engine doesn't generate a great deal of excess heat from a cold start, perhaps this defrost ability is true of petrol engined Volvos. To be fair, I haven't tried to sit and wait in the car for 3 minutes for ice to defrost so I'm willing to give it a try if time permits.

Thank you all for the replies, I'll update if I find anything interesting.

yes diesels never used to generate much heat when idling but modern ones have coolant just circulating around the head when cold so it warms up very quickly now , the coolant starts going around the block after it has warmed up .
Regarding wiring , each car has an individual wiring loom suitable for the things it has fitted . You can't buy a general wiring loom , they are made to order for each VIN .

[apersson850]

Diesels sold in the Nordic countries had diesel driven auxiliary heater as standard. Not any longer, though. In the 90-series today, you have to buy an optional climate package to get the heater. But I can start my heater remotely before I go away, so no ice to remove by hand.

[psq43]

I'd like to bring this back to life if I may.

I've just had a new heated screen fitted in my 2017 S60. The previous owner had clearly had conventional glass put in for reasons unknown, but I wanted the heated version. All the wires and cables were present, and the button and dash display indicate it should have a heated front screen.

It went to the dealers, and came out with a heated front screen that doesn't get hot.

It went back in, they said they found a dodgy earth behind the interior mirror area, and now all was well. But it wasn't. Still not heat to screen.

So it's just been in for a 3rd go, all day long, and they're saying they can't really find what's wrong without taking most of the dash out, or it could be a control module, and be very costly and time consuming

Does this sound right to you all?

[Clan]

Originally Posted by psq43

I'd like to bring this back to life if I may.

I've just had a new heated screen fitted in my 2017 S60. The previous owner had clearly had conventional glass put in for reasons unknown, but I wanted the heated version. All the wires and cables were present, and the button and dash display indicate it should have a heated front screen.

It went to the dealers, and came out with a heated front screen that doesn't get hot.

It went back in, they said they found a dodgy earth behind the interior mirror area, and now all was well. But it wasn't. Still not heat to screen.

So it's just been in for a 3rd go, all day long, and they're saying they can't really find what's wrong without taking most of the dash out, or it could be a control module, and be very costly and time consuming

Does this sound right to you all?

No it doesn't ..

was the car specified with one on the factory build sheet? any dealer will be able to look it up..

The cables are not under the dash they are under the scuttle , you will need to remove the wiper arms and plastic plate all along the base of the windscreen. there are 3 thick wires , one at each end and one in the centre .

But make sure the car was built with one or it wont work even if wired in ..

[psq43]

Originally Posted by Clan

No it doesn't ..

was the car specified with one on the factory build sheet? any dealer will be able to look it up..

The cables are not under the dash they are under the scuttle , you will need to remove the wiper arms and plastic plate all along the base of the windscreen. there are 3 thick wires , one at each end and one in the centre .

But make sure the car was built with one or it wont work even if wired in ..

Hi there.

Yes it was fitted with a heated front screen from new. The dash display gives options for both electric and fan when activating it. For reasons unknown, prior to me buying it as a used car, the screen was replaced with a standard one.

Apparently all fuses are present, the cables you mentioned are all present and all this has been tested. When turning it on, there is an audible 'click' coming from the glove box area, and again when it turns itself off after 4 minutes or so.

However, zero heat is going into the screen, although this itself has also been tested and current does pass through it.

They suspect a control module fault, but as this requires much digging, that's about as far as they want to go under any guarantee or warranty.

[Clan]

Originally Posted by psq43

Hi there.

Yes it was fitted with a heated front screen from new. The dash display gives options for both electric and fan when activating it. For reasons unknown, prior to me buying it as a used car, the screen was replaced with a standard one.

Apparently all fuses are present, the cables you mentioned are all present and all this has been tested. When turning it on, there is an audible 'click' coming from the glove box area, and again when it turns itself off after 4 minutes or so.

However, zero heat is going into the screen, although this itself has also been tested and current does pass through it.

They suspect a control module fault, but as this requires much digging, that's about as far as they want to go under any guarantee or warranty.

It wants some basic tests doing on the 3 thick wires if the voltage and CURRENT and earth are good then it can only be the screen ...Is it genuine volvo screen ? Have you tried it with frost on it ?

[psq43]

Originally Posted by Clan

It wants some basic tests doing on the 3 thick wires if the voltage and CURRENT and earth are good then it can only be the screen ...Is it genuine volvo screen ? Have you tried it with frost on it ?

All this has been done and shows both the screen and the cables are good.

Yes, tried it with both thick and thin layers of frost, and with misting. Absolutely nothing happens.

[Clan]

Originally Posted by psq43

All this has been done and shows both the screen and the cables are good.

Yes, tried it with both thick and thin layers of frost, and with misting. Absolutely nothing happens.

so how much current is flowing through each element? What is the feed voltage , What is the resistance of the element measured from the centre to each end ? ( there are two elements, a left and a right with a relay under the dash for each one )

[psq43]

Originally Posted by Clan

so how much current is flowing through each element? What is the feed voltage , What is the resistance of the element measured from the centre to each end ? ( there are two elements, a left and a right with a relay under the dash for each one )

This, they didn't share with me.

My other private mechanic, has suggested I take it to another volvo dealer, tell them nothing except the heated screen doesn't work, and see what they come up with.