Mk4 Heated Screens

[Criot]

Has anyone had issues with heated screens not working on new MK4? Both front and rear windscreen heaters didn't seem to work at all today in the rain, front cleared as normal with fans but rear showed no signs of movement at all, the top of the front was left uncleared by fans and normally these would clear with the heated front windscreen but again, no sign of clearing on front either - They've both worked fine before although I noticed the rear window didn't seem to clear as fast as my old MK3 but it wasn't a major issue. Fuses seem to run off different ones so that probably rules them out but will probably check them at some point. Is there a relay that runs just the heated windscreens for example? Obviously with us getting in to summer its going to be hard to confirm if they are or aren't working, hopefully next time i'm out in it its raining and I can try again to see if they still aren't clearing.

I'd rather try and see if I can confirm if theres an issue first (especially before winter when i'll need them) before booking it in with Ford. Anyone else had similar issues or know of similar issues?

 

[ianincheshire]

Has the car not been used for a while ? If the battery is not fully charged then I suspect the heated screen won't work.

Easy way to tell, does stop/start work ? That's the first thing that stops working if the battery is not sufficiently charged

[pragmatix]

I suspect a not fully charged battery.

[mjt]

This implies the designers have prioritised battery condition over road safety. If so it's an approach I would take issue with. The alternator ought to be perfectly capable of sustaining those loads and still be able to charge the battery so there's no excuse for it.

[Wino]

I know ours wont work together on the Mk4 So its windscreen first then rear window which I presume is designed to save the battery although they both worked in tandem on the Mk3.

[rayferry]

As above your battery is not fully charged so it goes into power save mode and it starts to turn things off, start stop function, front and rear heated screens, keyless entry turns off on all doors except the drivers door, auto hold system turns off randomly.

I did read on another thread a battery drain update was available which may help with this issue and of course multiple other updates for the Mk4 software.

I really cant understand why the alternator cannot run all systems under normal running conditions and why the battery is only charged to 80%.

I am waiting until things return to a normal to book my Mk4 in for a full software update it could take three days at the dealer to update all systems.

And don't get me started on the F9 map upgrades!!!!

[ianincheshire]

It's all down to the strive to get the emissions figures down. If you limit the alternator charging, then you reduce ( ever so slightly ) the power needed to drive the alternator. Reduces the load on the engine and therefore emissions.

As they say 'every little counts' especially in the competion for apparent low co2 figures

[mjt]

In that case just leave all the power hungry "toys" off completely! Then we can all learn how to control our cars properly without all this unnecessary gadgetry.

I'd keep the heated screens though

[Ennvoqation]

48 minutes ago, mjt said:

In that case just leave all the power hungry "toys" off completely! Then we can all learn how to control our cars properly without all this unnecessary gadgetry.

 

That's what Caterham's are for, no fancy gadgets just pure driving fun. 

[rayferry]

Another owner reported that his alternator was faulty (excessive ripple) and the dealer was going to replace it.

I am going to get mine tested at the dealer when I get the software updates installed.

[Criot]

Interesting, thanks for the feedback all. It seems crazy that a low charge battery wouldn't allow the heated screens to work, you would've thought they'd go on the alternator, it's only going out once a week at the minute with covid for the shopping so I guess i'll probably take it for a good run now that restrictions are lifted and give it a good charge.

Will the software update actually resolve this does anyone know? It's obviously not due for a service for another year (I do low milage so will be service every 2 years), and don't really want to have to take it in until then. Unless of course these software updates will fix the issue and will save me from potentially having these issues in the winter?

Thanks!

[Criot]

Just to reopen this subject does anyone know if the battery drain issue still exists and requires software update? Having major issues with the battery being almost flat, cars only going out once or twice a week as im on furlough. I took it out for a decent run up the motorway the other week and it was pretty much dead today, as well as it going out last weekend for about a 15 mile round trip.

[Wood Gnome]

Had this problem from new (Aug 2019) heated screens not working due to the ridiculous emissions, and charging the car battery.

Booked it into Fords had it all weekend, the outcome was, nothing wrong with the car, just need to drive it longer than 30 mins each trip, this is from the service manager BTW, also he said he wife has the same car and he charges it up regularly via a mains battery charger.

So you can have heated seats, but not the screens, comfort over safety really poor show from Ford this one didn't have it on my other Ford's, maybe its a ploy to get you use to plugging your car in every night when we have to go full EV.

 

 

[Zippyh]

So after unanimously agreeing we all have the same fault how do we convince Ford they need to cure it before warranties end???

[Criot]

On 1/20/2021 at 10:27 PM, Zippyh said:

So after unanimously agreeing we all have the same fault how do we convince Ford they need to cure it before warranties end???

There is apparently a software update to improve this, not had it done on mine yet but it'll be going in for a service soon so i'll see how they are after its been done.

[FezMan]

My Start/Stop has never worked since I bought the car in September, dash always says 'not working due to battery charging' 

after 4 months I decided that its had enough 'charging' and took it to Ford, who diagnosed a faulty battery and ordered a new one which ill have fitted this week.

Could you/did you take it to Ford under warranty and get them to have a look? If your S/S also barely works (or in my case never) take it in for that reason and they might diagnose yours with a faulty battery too, which might fix the heated screen issue

[FatHead1979]

3 hours ago, Criot said:

There is apparently a software update to improve this, not had it done on mine yet but it'll be going in for a service soon so i'll see how they are after its been done.

Don't forget to report back post update and also see what details (if any) you can get out of the dealer in relation to exactly what the update changes etc.

[SB active X estate]

You tube video today from My-Ford-Focus says some cars got the wrong BMS sensor installed which prevents auto start stop from working. 

[Midgeman]

Very interesting video and may confirm what I have suspected for a while now as my vehicle has suffered from Charging System Fault messages since day one but the Dealership had it a couple of times but all they did was put it on charge and then said that the battery was fine and gave me the vehicle back so I gave up with them in the end. However I did try an experiment where by I disconnected the BMS Sensor from the battery for a while and never had the message while disconnected but maybe the BMS Wire has to be connected to get the message anyway?.

I have just checked my vehicle and the BMS on the Negative side of the battery has the same code as the OLD one shown on the YOUTUBE VIDEO so maybe it is the problem I will need to speak to the Dealership when Covid 19 permits.

[Criot]

19 hours ago, FezMan said:

My Start/Stop has never worked since I bought the car in September, dash always says 'not working due to battery charging' 

after 4 months I decided that its had enough 'charging' and took it to Ford, who diagnosed a faulty battery and ordered a new one which ill have fitted this week.

Could you/did you take it to Ford under warranty and get them to have a look? If your S/S also barely works (or in my case never) take it in for that reason and they might diagnose yours with a faulty battery too, which might fix the heated screen issue

I’ve not took mine yet but my issue now seems to be battery drain - cars going out about twice a week at the minute, and it was flat today (would not start at all, had to go for jump leads!) Halfords have tested the battery and said its ok.

 

Going to ring tomorrow and try to get it booked in this week, Halfords suggested I either use it more or put it on charge, if i wanted the latter i would’ve bought an electric! I understand that at this time of year especially it’s an issue but for it to not start at all 5 days after last use and a decent run, i’m not happy! If Ford can’t find anything wrong with it i’ll likely be doing a part ex in all honesty and getting rid!

[Wood Gnome]

Hi All,

Does anybody have an idea of the cost of the BMS unit, might be something we could buy and fit to over come this problem, I'll check mine later today see what version I have on my 2019 Mk4.

[Wood Gnome]

Just checked my BMS unit and its the same as the old one in the youtube video.

Will email my dealership and ask the question about switching it. 

[FezMan]

Also just checked mine and I have the apparent 'incorrect' one with the BC ending installed. 

Had my battery replaced with a new one last week after taking it in due to the S/S having never worked Ford diagnosing it as faulty batter. They ordered and fitted me a new one, picked it up and the S/S worked on the day.. Hasn't worked again since.

Im no Ford techniction so I don't know if they're supposed to replace that BMS sensor if they fit a new battery, but either way the car will be going back in as my S/S is still not working, but ill mention that to them this time to see if its of any help as they say they struggled to find the issue last time

 

[Paul9619]

I’ll monitor this thread as my recent purchase of a 2019 TX estate has never has the stop/start working yet. It doesn’t actually bother me but may as well track while it’s still under warranty. 

[Criot]

Just an update Ford had my car on Tuesday, could not find any issue with the battery drain but did updates to fix the "Emergency call system malfunction", GPF recall and so on. When I get in now my SYNC no longer shows the "Powering off systems to save power" message as it did before, however it never did this when I first got the car so I'm assuming these updates have potentially solved this issue.

I pretty much always disable my start stop so can't comment on that but generally the few times i've enabled it it has worked, and heated screens seem to work fine now as well.

The only issue I have now is that DAB no longer seems to work on the radio... Cars sat outside currently running a SYNC update over wifi so we'll see if that remedies it, if not, it's going back in for that to get fixed.