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Large MPVs -- Ford Galaxy / VW Sharan / SEAT Alhambra: => Ford Galaxy / VW Sharan / SEAT Alhambra => Topic started by: regw on December 31, 2020, 01:57:21 PM

Title: Screen heater elements
Post by: regw on December 31, 2020, 01:57:21 PM
I suspect I'm flogging a dead horse here but the screen defroster switch
at the console only works at the extreme right or left of the screen.
The wiring diagram in the hyenas manual shows right and left elements
each of which I assume contain multiple parallel heater elements.

It's probably some of the elements in each channel broken and only a new screen
( which aint going to happen) would improve

Not a major disaster and I can live with it unless someone has insights or cunning wheezes to
get then working again?
Title: Re: Screen heater elements
Post by: SirDavidAlhambra on December 31, 2020, 02:47:15 PM
Not sure but I will try and find out by looking in the internet and so on

I think there may be separate fuses for different parts of the screen, have you checked that as a starting point my friend

This is a useful feature to have and it would be good to help you get it working
Title: Re: Screen heater elements
Post by: johnnyroper on December 31, 2020, 04:45:19 PM
More than likely the connection on the defective side of the screen has detached,they have been known to fail in the past. Probably a replacement screen job
Title: Re: Screen heater elements
Post by: regw on December 31, 2020, 08:41:18 PM
Thanks guys but as both sides work, albeit partially,
I doubt its a connector dropped off but the elements failing.

It isnt a serious issue for me luckily and certainly doesn't warrant a new screen

We never had screen heaters when I were a lad....... :D
Title: Re: Screen heater elements
Post by: johnnyroper on December 31, 2020, 08:49:42 PM
Sorry I read it wrong thought it was just one side not working. Yeah you got some dead elements in your screen by sound of it
Title: Re: Screen heater elements
Post by: SirDavidAlhambra on December 31, 2020, 08:58:33 PM
Back in the day I used to boil the kettle and pour it over the windscreen, people said it would shatter but it never did (do not try it though!!! Modern cars might not be as strong). Then I would spray de-icer all over it and get the blower working on it until the car warmed up. I found keeping the window open a notch and using a chamois to keep wiping the screen worked best. But if u got ice on the outside as u were driving then that was a real problem

 cya
Title: Re: Screen heater elements
Post by: johnnyroper on December 31, 2020, 10:56:09 PM
Donít need to scrape mine just fire engine up and put on screen demist and itís cleared in no time due to an electric pre heat element. Not quite as quick as the heated screen but not much different.
Title: Re: Screen heater elements
Post by: regw on January 01, 2021, 12:13:18 AM
Just out of interest,
I was surprised to see its fed via a 50A fuse.
I doubt it would draw much current of course, but even at say 40A@14.2v thats 568 watts
which is a third of the alternators rated output! 120A@14.2V
No wonder its on a timer.



Title: Re: Screen heater elements
Post by: insanitybeard on January 01, 2021, 08:37:37 AM
And also why it won't activate if the engine isn't running! They do use a lot of juice for sure, presumably a lot more than the rear screen due to the much greater number of elements.

Johnny, how do those pre-heaters work? Is it just an electric element in the blower box which warms the air stream as it's blown through? Guess it still needs a lot of power but gets around having to embed elements in the screen (which I believe is a Ford patent which other manufacturers have to pay a licensing fee to use).
Title: Re: Screen heater elements
Post by: johnnyroper on January 01, 2021, 12:41:06 PM
Yeah itís just an electric ptc heater unit within the heater box,think it is only activated below a certain temp or if full screen demist is selected. Also inactive below a certain coolant temp switches off once coolant temp high enough to take over. Size of cables suggests it draws some current though.

Fired car up this morning to shift the ice whole car was done in a few minutes so it probably is a better system to having screen heater only even if itís marginally slower clearing the screen.
Title: Re: Screen heater elements
Post by: SirDavidAlhambra on January 01, 2021, 01:28:29 PM
So impressive, you guys put all the best little modifications in your cars, you really do
Title: Re: Screen heater elements
Post by: johnnyroper on January 01, 2021, 05:40:19 PM
So impressive, you guys put all the best little modifications in your cars, you really do

Itís not a modification it is factory fit equipment on BMWís with Diesel engines
Title: Re: Screen heater elements
Post by: SirDavidAlhambra on January 01, 2021, 06:43:21 PM
Ah, understood. Fairly impressive feature nonetheless!

Rumour has it you can get these things that plug into the mains and get your coolant nice and hot before you set off, they use them in Canada so that the engines start ok in the cold weather (oil can be too viscous otherwise)