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Radio and rear heated screen issue


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n33712
New User

Mar 15, 2023, 5:52 AM

Post #1 of 12 (1727 views)
Radio and rear heated screen issue Sign In

Hi

Have a 2017 Audi A6 Saloon 2.0.
Issue is whenever i turn on the rear heated windscreen i lose all radio signal (DAB, FM, AM) Occasionally, for a short while, i guess when signal is really strong, it still works but very crackly etc.
The rear heated windscreen is really poor as well - not sure related though.

I have researched this issue and everyone suggests on other posts that there is likely a break in the circuit in the rear window, as these are the aerials as well......but there is one big difference....this only occurred when i replaced the car battery.
It could still be the circuit in the window and did not occur previous as maybe not enough current was going through it?
Could it be anything else?

Appreciate any advice :)

Many thanks


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 15, 2023, 6:11 AM

Post #2 of 12 (1722 views)
Re: Radio and rear heated screen issue Sign In

My best guess is that the rear window needs to be replaced. It appears the electrical current of the rear defroster is interfering with the antenna reception.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



n33712
New User

Mar 15, 2023, 6:46 AM

Post #3 of 12 (1713 views)
Re: Radio and rear heated screen issue Sign In

Okay, thanks. Suspected that but was not sure if there was anything else I can rule out


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 15, 2023, 6:58 AM

Post #4 of 12 (1703 views)
Re: Radio and rear heated screen issue Sign In

Argh? 95% of rear window/screen (same) the defroster/defogger with lines is ON the glass not inside it. Things scratch that up one or more will not work.

IDK this exact car how antennae is done many are just a lump thing up top on rear wiring could be routed to moving glass there assorted tricks you can see how power gets to glass.

If confused I think the set up is like this the exact car not sold to the US doesn't matter that's how they do that stuff.

Some of those RWD lines with a flashlight you can see breaks in them there is a copper loaded tiny nail polish if one or more broken is a patch the real fix is a new glass.

Guessing but I'd be looking there expecting antennae and wires may go close there stressed out?

Tom
PS: Check a RWD (rear window defogger) when not in use by the right time/temp can breathe on glass when it's just turned on see which area or line doesn't take the foggy glass clear!



n33712
New User

Mar 15, 2023, 7:27 AM

Post #5 of 12 (1689 views)
Re: Radio and rear heated screen issue Sign In

Appreciate the advice.....will definitely try some testing. Have also heard that on a really dark night with the heater on you can sometimes see small sparks as the current jumps the break......not 100% sure on this but worth a go. Thank you


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 15, 2023, 7:56 AM

Post #6 of 12 (1687 views)
Re: Radio and rear heated screen issue Sign In

Never heard of that one but I suppose it's possible.

A break in the heating element isn't what you're looking for anyway. That in itself wouldn't effect the radio reception.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 15, 2023, 8:14 AM

Post #7 of 12 (1681 views)
Re: Radio and rear heated screen issue Sign In

Sorry for the book. I was thinking (just a maybe) that RWD uses a LOT of power (larger gauge wire) if antennae is near or wire to it are rubbing from would be a moving rear window with defroster ON glass. How done? Touch things or a cable that flexes? IDK it was a thought for why is all,
Tom


Sidom
Veteran / Moderator
Sidom profile image

Mar 15, 2023, 11:44 AM

Post #8 of 12 (1661 views)
Re: Radio and rear heated screen issue Sign In

I'm not sure what type of diagnostic equipment you have available to you. I would start out with the simple stuff.1st since the problem started right after battery replacement, I would Swap the battery with a known good one to be sure that's not the problem. Cleaning the terminals and all connections really well While the battery is out. After that you wanna check all the fuses make sure they're good.
Also you wanna check your charging system Voltage while the RWD is on. the rear window defroster uses a lot of current and if The alternator is defective, the RWD could be pulling down the charging voltage when it's on.

After that you're gonna need to look at some scan data From the radio While the problem is happening. Also checking powers in grounds at the radio to see if anything is being pulled down.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 15, 2023, 1:01 PM

Post #9 of 12 (1654 views)
Re: Radio and rear heated screen issue Sign In

This car exactly isn't sold to the US, just BTW so some guessing how from 1st post the antennae and "Rear Window Defroster" (= RWD) for this ARE both on the same glass?

We are trying I can't know how wiring is routed to these items but would be out of normal eyesight looking for where the two share something in common as it does it then both are weak.

All suggestions include even battery power especially while RWD is on is clearly interrupted or as now Sidom mentioned draws whole battery voltage down - seconds or longer.

If you can't check voltage drop, even at a power port (I think universal size) test one should be battery voltage.

I personally haven't noticed both an antennae and RWD on the glass once some were put inside front windshields - only some GM cars OMG ages ago now metal wipers screwed up the radio on many! Dang I'm getting old! :-)
Tom



n33712
New User

Mar 15, 2023, 1:43 PM

Post #10 of 12 (1648 views)
Re: Radio and rear heated screen issue Sign In

Thank you Tom and Seldom

Will try and do some testing this weekend and see what i can come up with.

Yes, believe both are on the same glass.

I have a voltmeter and a Ancel VD700, there are no error odes on the car


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 15, 2023, 1:54 PM

Post #11 of 12 (1642 views)
Re: Radio and rear heated screen issue Sign In

OK - Look for voltage to read below about 10.5 or 11V should trigger a warning on dash? If it stays about the same or range (engine running @ idle even) stay between about 12.9 not much more than 14.8V ever or out of that range the vehicle will be confused.

You are able to look right at where the two item meet if (you need to say) this window/windscreen (we get that) shares moving wire that's the likely problem spot? Otherwise they have nothing to do with each other IMO and experience, Tom


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 15, 2023, 2:24 PM

Post #12 of 12 (1634 views)
Re: Radio and rear heated screen issue Sign In


Quote
there are no error odes on the car


You don't have the equipment to read Sim and body modules.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Mar 15, 2023, 3:03 PM)






 
 
 






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