Hey folks,

after puzzling over why my DAB radio would cut out, I’ve discovered I have a dodgy element on the rear heated screen which is causing interference as I understand it.  
However, I’ve noticed that as it’s been really cold recently -9 onwards, that the radio still cuts out even when I haven’t activated the rear screen.   
 

I’m sure it’s just weather affecting the signal and as it uses the stupid rear window for an aerial the weaker the signal the worse it gets.   It made me wonder though, is there a setting in the car that if the temp gets low enough, it auto activates the heated rear screen without lighting the button?   I feel Ford have form for this as  I had a 53 plate Focus Ghia that when you routed airflow to windscreen, it auto activated the heated front screen without lighting the led.  Dealer told me that it was normal and pointed to the manual - I only noticed as the fuel consumption was poor.  
 

its only a single line and a wee strip that doesn’t defrost, but knowing my luck it will get worse (not sure why it failed to begin with!) anybody replaced a rear screen via a dealer - how much does it cost?
 

Another question, does the Mkv 2017, have heated washer nozzles?   Previous focus models I’ve owned had them and they activated with the heated front screen, but unsure if the mondeo does or not?

thanks guys,

lat

1 hour ago, The Latman said:

after puzzling over why my DAB radio would cut out, I’ve discovered I have a dodgy element on the rear heated screen which is causing interference as I understand it.  

the loss of one heating element will not make any significant difference to the DAB signal reception. It will not cause any interference with the signal.

1 hour ago, The Latman said:

However, I’ve noticed that as it’s been really cold recently -9 onwards, that the radio still cuts out even when I haven’t activated the rear screen.   

The use of the heated screen can not affect the DAB signal. There is an aerial amplifier and combined isolator fitted between the heated screen and the aerial which blocks any DC component. It is of course quite possible to have a defective aerial amplifier which a number of people on the forum have had over recent years. A major problem of interference with the DAB signal in cars is the use of dashcams, in particular the use of rear mounted dashcams fitted on the rear window.

1 hour ago, The Latman said:

I’m sure it’s just weather affecting the signal and as it uses the stupid rear window for an aerial the weaker the signal the worse it gets.

Actually the use of the rear window as an aerial is quite clever and extremely reliable, and similar combined heated screens / aerials are use on a range of military vehicles.

The weather does affect the propagation of all radio signal and some are affected more than others. DAB signals are not ideal for vehicles in general and poor atmospheric conditions can attenuate the signal considerably. It therefore follows the weaker the signal the less that will be received. 

1 hour ago, The Latman said:

It made me wonder though, is there a setting in the car that if the temp gets low enough, it auto activates the heated rear screen without lighting the button?

Perhaps on future Ford vehicles this may be something they will introduce, but as of this date the rear heated screen dose not automatically turn on. It can however automatically turn off.

1 hour ago, The Latman said:

its only a single line and a wee strip that doesn’t defrost, but knowing my luck it will get worse (not sure why it failed to begin with!) anybody replaced a rear screen via a dealer - how much does it cost?

They are easy enough to repair with a little bottle of conductive paint (about £10)

speaking of heated screens, are the fronts on a timer ?, mine turns itself off after a while.

Front and rear are both on timers. The exact time seems to be dependent on the model and the year.

Typical time for the front screen is around 4 minutes.

Typical time for the rear screen is around 10 minutes (some older models may not have a timer)

Talking of winter related issues......

Whats peoples thoughts on tyre pressures in the cold weather ? 

Ours are normally kept at 32psi but with the cold weather they are showing 28/29psi 😮

1 hour ago, unofix said:

the loss of one heating element will not make any significant difference to the DAB signal reception. It will not cause any interference with the signal.

The use of the heated screen can not affect the DAB signal. There is an aerial amplifier and combined isolator fitted between the heated screen and the aerial which blocks any DC component. It is of course quite possible to have a defective aerial amplifier which a number of people on the forum have had over recent years. A major problem of interference with the DAB signal in cars is the use of dashcams, in particular the use of rear mounted dashcams fitted on the rear window.

Actually the use of the rear window as an aerial is quite clever and extremely reliable, and similar combined heated screens / aerials are use on a range of military vehicles.

The weather does affect the propagation of all radio signal and some are affected more than others. DAB signals are not ideal for vehicles in general and poor atmospheric conditions can attenuate the signal considerably. It therefore follows the weaker the signal the less that will be received. 

Perhaps on future Ford vehicles this may be something they will introduce, but as of this date the rear heated screen dose not automatically turn on. It can however automatically turn off.

They are easy enough to repair with a little bottle of conductive paint (about £10)

Thanks for all this.   The reason for my deductions were two fold:  1.  When I turn on the rear heated screen, the radio completely cuts out.  Turning it off brings the radio back.  2.  I’d read somewhere that an element outage can cause it?

I noticed the radio cutting out with the rear heated screen last week, yesterday the radio started intermittently cutting out, but the weather has been shocking.

 

1 hour ago, Wino said:

Talking of winter related issues......

Whats peoples thoughts on tyre pressures in the cold weather ? 

Ours are normally kept at 32psi but with the cold weather they are showing 28/29psi 😮

Because of Atmospheric pressure.

36 minutes ago, The Latman said:

 1.  When I turn on the rear heated screen, the radio completely cuts out.  Turning it off brings the radio back.

That would suggest a defective aerial amplifier/isolator unit. I think on the Mondeo hatchback they are located in the tailgate. Very often there are two different modules, one for FM and one for DAB

 

1 minute ago, eddie eastwood said:

Because of Atmospheric pressure.

No because of Boyle's Law.

A gas expands or contacts with temperature and if contained in a fixed vessel (tyre) the pressure will increase or decrease.

@StephenFord is the physics guy to answer this.

23 minutes ago, unofix said:

No because of Boyle's Law.

A gas expands or contacts with temperature and if contained in a fixed vessel (tyre) the pressure will increase or decrease.

@StephenFord is the physics guy to answer this.

Now, Boyle's law was one of the more useful things I learned at school (though I still remember the 'quadratic formula' but have never used it since my maths A level LOL I just got the following from Wiki, "

Boyle's Law states that when the temperature of a given mass of confined gas is constant, the product of its pressure and volume is also constant. When comparing the same substance under two different sets of conditions, the law can be expressed as:

Boyle's Law states that when the temperature of a given mass of confined gas is constant, the product of its pressure and volume is also constant. 

Basically that was the basis for my initial thoughts on the pressure in the tire, which should remain constant no matter what size wheel you upgraded to, but it's been a while since I was in a classroom so have probably recollected it all wrong LOL

EDIT

I really am having an off day LOL Thought I was responding to an old thread about tire pressures for different sized wheels, just ignore the whole of my post. It's late for me and I need my mug of Horlicks...

 

47 minutes ago, unofix said:

That would suggest a defective aerial amplifier/isolator unit. I think on the Mondeo hatchback they are located in the tailgate. Very often there are two different modules, one for FM and one for DAB

 

Ok, thanks for all the advice Unofix.  Much appreciated. 

I’ve located a couple of wee nicks in the affected heating strip, I’ll invest in the conductive paint, seems easy enough after watching a couple of YT vids. 

8 minutes ago, The Latman said:

I’ll invest in the conductive paint,

 

On 11/26/2022 at 5:24 PM, unofix said:

Yes they work well if you are prepared to spend a little time and do the preparation needed.

Find the break in the track. Use something like 'scotch brite' and gently and carefully clean about 10mm either side of the damaged section. The darker protective coating on the track needs to be cleaned away until you reach the actual conductive part of the element.

Clean the area with IPA and allow to dry. Use masking tape or electrical tape to mask either side of the track and create a perfect parallel channel. Now paint on the silver conductive paint and allow to dry. paint on a second coat and allow to dry. Finally cover the repaired area with clear nail polish. Leave overnight before removing the tape and switching on the HRW.

 

One more winter related question.   Where’s the fuse for the windscreen washer pump?

the manual shows a fuse for the rear washer pump but I can’t see one for the front?

16 minutes ago, The Latman said:

One more winter related question.   Where’s the fuse for the windscreen washer pump?

the manual shows a fuse for the rear washer pump but I can’t see one for the front?

It's the same pump but goes in reverse with a 2 way valve

7 hours ago, iantt said:

It's the same pump but goes in reverse with a 2 way valve

Great.  Thanks. 

Interestingly today, the radio initially just barely worked with or without heated screen being on, on either DAB, FM or AM, then about 20 minutes later it behaved itself.   After doing some googling, it appears there may be 2 of these amplifier/isolaters in the tailgate, Im a telecoms field engineer and find it funny that both components could misbehave at the same time?

Are these modules easy to replace, looks like getting to them might be the trickiest bit.

Sorry for all the questions, its pretty difficult to get answers elsewhere and if I go to a dealer they'll surely charge me a small fortune.

Back on topic unusual for me LOL, can the OP not retrofit a roof ariel, or one of the old school mount in the wing job ? just a thought.

3 minutes ago, Jimpster said:

Back on topic unusual for me LOL, can the OP not retrofit a roof ariel, or one of the old school mount in the wing job ? just a thought.

Or, a really cheap Halfords MagMount at £10 LOL

 

12 hours ago, unofix said:

That would suggest a defective aerial amplifier/isolator unit. I think on the Mondeo hatchback they are located in the tailgate. Very often there are two different modules, one for FM and one for DAB

Yes as said, there are very often 2 units. If the isolation of either unit fails it will allow DC on to the aerial circuit.

Here they are on my 2015 Titanium X, top of the tailgate

 

OK, thanks for this.  I did a quick google, they dont seem to be that expensive to replace, and don't look too difficult to swap out.  Is the tailgate cover easy to take off?   When I was in my 20's i did a lot of dabbling with my cars, far cry from those late 80's / 90's cars to this one though!

Hit a new record for this area -7, car sounded decidedly tappity when first started, maybe not tappity but didnt sound right till it warmed up. I HAD to go out for my Retinopathy test.

YES i know your not supposed to drive back after but ive had no issues in the 10 years i've been having them.

1 minute ago, Jimpster said:

YES i know your not supposed to drive back after but ive had no issues in the 10 years i've been having them.

Sshhh... I too drive home after getting the eye drops, no problems either apart from this year when the sun was shining! I know, in Northern Ireland, who'd have thought! I knew those prescription sunglasses would come in handy one day LOL

11 hours ago, StephenFord said:

Sshhh... I too drive home after getting the eye drops, no problems either apart from this year when the sun was shining! I know, in Northern Ireland, who'd have thought! I knew those prescription sunglasses would come in handy one day LOL

It did seem a little brighter yesterday even with my reactive lenses, had to drop the visor.