Heated Screen Works Sometimes!!

[dan0235]

Hi there, guys and gals

My 52 reg mondeo tdci graphite heated screen has stopped working properly, the light sometimes comes on the button once its pressed but once its released it goes out, other times i press the button and while i'm pressing the button the light goes out! i've checked the fuses, does outside temp have something to do with this??

any help would be greatly appeciated

thanks

Dan

[fishpond 47]

Hi there, guys and gals

My 52 reg mondeo tdci graphite heated screen has stopped working properly, the light sometimes comes on the button once its pressed but once its released it goes out, other times i press the button and while i'm pressing the button the light goes out! i've checked the fuses, does outside temp have something to do with this??

any help would be greatly appeciated

thanks

Dan

I would say the switch is at fault/faulty, no the outside temp does not make any difference.

[dan0235]

update to post,

i got in the car today, no ice on window, tried the screen switch it worked as it should, noticed OAT (outside air temp) was +5 degrees c, i'll try it again with differing air temps.

i'm thinking that its somehow linked with the 'ice warning light' which comes on if temp is below +5 C, if so, does anyone know how to bypass this, as i don't see the point of having a heated screen if you can only use it once the ice melts its self!!

[dave h]

Hi Dan 0235. the heated screen will work in any temperature and is not linked to the outside temperature, it sounds like the switch is at fault or possibly the relay like the previous answer said. Hope that helps Dave.

[mintalkin]

on some mk3 depending on the trim level the front and rear heated screens will come on automatically when the outside temp is close to freezing point,when starting the car the buttons will light up, so you could have trouble with the relay or something on the auto circut. but without inspection its hard to say what.

[dan0235]

Update again,

Located sensor, drivers side, behind lower portion of bumper.

Got in car, started engine, checked OAT it read 2 degrees c, screen heater didn't work.

Held sensor in fingers for 5 mins, checked OAT it read 7 degrees screen heater worked, turned off heater waited till OAT dropped to 6 degrees, screen still worked, 5 degrees it still worked, 4 degrees amber ice warning came on, screen didn't work !!!

Let temp go down to actual (2 degrees c)

I disconected the sensor, OAT failed to 20 degrees c and then didn't read, screen heater worked.

Going by this the screen is affected by temp.

I've left it disconnected for now to check if being disconnected has any detremental affects on the rest of the car, if not i'll leave it off, i think i can live without knowing the OAT!

I saw an advert for 'Autoglass' which was warning about chips in windscreens becoming cracks as windscreens are defrosted.

I'm wondering if this is what ford have done to try and stop screens cracking by isolating the heated screen under 4 degrees

Thanks for your help

Dan

[wimiu012uk]

Heated front screen operation is not dependant on outside air temp and will work at any temp, so i suggest you have a fault somewhere .

[dan0235]

Maybe.....but what problem??

Even so, its working now, with no apparent adverse affects, so gonna live with it, maybe reconnect it once the weather gets better!!

Maybe this thread may help someone with same symptoms and want a quick fix for a couple of months instead of tring to figure it out while freezing your .....toes.......off stood outside in this weather or paying an auto electrician to diagnose it.

Thanks

Dan