De-mister and Radio

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grufflybear

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Joined
May 15, 2008
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41
Location
Surrey
Have noticed a small but odd phenomenon.... when I switch on the rear window de-mister it causes heavy interference noise if I am trying to listen to the radio.... not exactly earth shattering issue of course but annoying if you want to catch the news and the dog has steamed up the back window etc.... I wondered if anybody else had noticed this effect (2007 E Class with Command).... It only affects radio not rest of Audio so I guess it is the current in the de-mister blocking the aerial but I would have thought that MB would have realised that in the design.
 
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Radio interference

I have exactly the same problem with my 55 reg E320CDI.
Has anyone found a cause and/or solution?
 
Many cars, including some Mercedes use the rear window demister elements as the aerial. If yours doesn't have a traditional sticky-up one then there is a very good chance that you have a HRW version. What happens is that the electrical connections to the heating element are not perfect and this manifests itself as noisy radio reception.

The cure is to carefully examine the connections and clean/recrimp/tension as required.
 
Thank you

Thank you - I inspected connections as suggested - seems to have made an improvement and my car clearly does have HRW type aeriel so at least I understand the issue now...
 
The actual FM/AM TV antenna "wires" are separate from the rear window defroster wires but the high current for the defroster and the close location make the antenna system sensitive like for bad connector contacts for the defroster wiring.
 
My 1999 W220 S320 does this also, and its always annoyed me..... Will check the connectors, thanks for a useful topic!
 
Hi

Every time my Mercs have gone to the main dealer, they come back with a scratch or excess mileage. I am therefore concerned what work would need to be carried out. My car is under warranty & next service is a long way off but may wait until then.
Thanks in advance

(((my mb is a 2007, c class avgt, 180k auto four door, about 11 k on the clock now)))
 
The actual FM/AM TV antenna "wires" are separate from the rear window defroster wires but the high current for the defroster and the close location make the antenna system sensitive like for bad connector contacts for the defroster wiring.

the previous w203 i had was ok. The cd is ok. Hover, recently noted that theradio reception is generally poor..lose wire?
 

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