Heated screen / battery voltage problem

[Guest]

Hello - I hope someone out there is able to help.

Our 2017 SMax doesn’t seem to want to activate the heated front screen every time it’s switched on. The light comes on the switch but the screen doesn’t heat.  Under warranty it went back to the dealer who said it was due to battery low voltage.  A drain test showed the battery to be ok and the alternator appears to be working ok too.

Yesterday morning the screen did work ok, probably only 12hrs after it was last running. Tomorrow I will test it again, as the car will have stood for 2 days.  I’ll also take a battery voltage measurement before starting.

Auto start stop and heated seats do work ok.

Local dealer wants the car again for a few more days to test for drain and to do further checks.

Has anyone else come across this, particularly anything related to devices draining the battery.  Does the WiFi pairing look to my home WiFi go to sleep correctly?  Does leaving the iPhone USB cable plugged in to the dash cause the CPU to stay awake and drain current (with no phone connected), etc.

Any pointers appreciated so I can assist the dealer.

[Meta55]

Hi hiz. Did you get an answer with your problem. My car goes into ford next week for this exact issue. 

[Guest]

Hi. After a few tries yes I think it’s sorted. They refused anything was wrong because the computer simply said the batter voltage was low. After a lot of calls they changed the battery though I tried to get them to tell me if the drain current was within spec but it was a slow and painful conversation which still hasn’t been answered.  We haven’t had too much frost this year annoyingly so I haven’t tested it as much as I’d have liked!

You sort yours? What was it?

[Meta55]

Hi Hiz. 

I never got an answer and told it was working when in garage, was tested by placing hands on screen. Like yourself, no real frost this year to test but if it’s not working this winter, the car will be back to be fixed properly this time.