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Discussion Starter #1
Hi everyone, as per the title, really...

I have a JVC head unit, fitted by a previous owner. Plays cds, also aux inputs, iPods, etc through a USB port in the glove box. Radio works without keys in the ignition, presumably because previous owner wanted it like that. But as soon as ignition is live, the reception gets overwhelmed by white noise.

I’ve had the head unit out, antenna connection etc look fine, special vw widget in place, etc. Powered antenna in the passenger door mirror earthed and working fine. But only with the engine off/no live ignition.

I don’t know much about these things, but I’d guess there’s major electrical interference happening somewhere to affect the powered antenna. But I’m stumped as to where it might be coming from, having checked all the radio wiring I can see.

Anybody else have this? Will I ever be able to listen to the radio while moving?

Cheers for any advice you can give!

ZGZ
 

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Discussion Starter #3
Usb chargers , fag lighter chargers, dash cams etc are all common for causing this .
Thanks for the quick reply. I’d already heard about that, and made sure there was nothing plugged into any accessory 12v socket. I’d developed a theory that the cable running to the leisure battery was too close to the aerial earth... but moving it didn’t make anything better, either... so still perplexed 🤔
 

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Discussion Starter #8
Ok, yes the presets remain. Headlights are wired for DRL, so are on sidelights (?) all the time when ignition is live. Could that affect things?

Thanks for trying to help!
 

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Hi everyone, as per the title, really...

I have a JVC head unit, fitted by a previous owner. Plays cds, also aux inputs, iPods, etc through a USB port in the glove box. Radio works without keys in the ignition, presumably because previous owner wanted it like that. But as soon as ignition is live, the reception gets overwhelmed by white noise.

I’ve had the head unit out, antenna connection etc look fine, special vw widget in place, etc. Powered antenna in the passenger door mirror earthed and working fine. But only with the engine off/no live ignition.

I don’t know much about these things, but I’d guess there’s major electrical interference happening somewhere to affect the powered antenna. But I’m stumped as to where it might be coming from, having checked all the radio wiring I can see.

Anybody else have this? Will I ever be able to listen to the radio while moving?

Cheers for any advice you can give!

ZGZ
Hi.
I found that when I disconnected the satnav aerial from the back of my radio it improved the reception.
 

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Discussion Starter #11
Just thinking aloud here , what units are in the headlights ? Some led drl have been linked to this .
I think you might have it right there - I wasn’t thinking of the led angel eye type front leds! Which presumably have some kind of transformers related to them... but god alone knows where they live?! (Just behind the lights themselves, I’d guess.)

So, if it’s the DRL function, how can I get them to stop interfering with the radio? Any ideas?

Hi.
I found that when I disconnected the satnav aerial from the back of my radio it improved the reception.
Thanks for the help, but the JVC head unit doesn’t have any sat nav capability! I’m fairly lo-tech with sat navs! (And many other things, come to think of it....)
 

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Discussion Starter #13
Cheers B&T, you’ll be interested to know you were spot on - it’s the lights! Unplugged both, and radio works fine.

If it ever stops raining here, I’ll investigate further this weekend. Thanks for your help!

ZGZ
 

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At least you know what to chase now 👍 .
Our old dash cam was a nightmare for interference, swapped it out snd it sorted it ....although radio reception was still pretty pants at times 😫.
Swapped the head unit recently and its like night and day.

Good luck mate .
 

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Discussion Starter #15
Until you said (being an electrical amateur myself), I’d never have guessed the lights were causing it...

Temporary solution today was to kill the DRL at the light switch (yellow and black, as opposed to black and yellow, on terminal 3, according to the confused Haynes very small wiring diagram.)

So until a permanent solution can be fathomed, I can listen to to radio. Except at times of darkness. Or low visibility. Or heavy rain.

But as I hardly ever go out at night anyway, and I don’t go out camping in the rain, or fog. With an OWL! (tm Fast Show, circa late 90s) that’s all good! (y)

Thank you as always for your quick help and advice (y)
 

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You don't say what year van you have, but don't forget that if you had DRLs from the factory (and replaced them with aftermarket units with LED DRLs) then they will be mandatory - so in theory you would need to reconnect them at MOT time, or it may fail (depending on whether the tester notices).
 

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Discussion Starter #17
You don't say what year van you have, but don't forget that if you had DRLs from the factory (and replaced them with aftermarket units with LED DRLs) then they will be mandatory - so in theory you would need to reconnect them at MOT time, or it may fail (depending on whether the tester notices).
Good point, thanks for the tip. (y)

(Van is/was T28/102 T5.1 2.0CR, first registered Nov 2011; don’t know if they were all running DRLs at that point - Haynes wiring diagrams seem to suggest it might have been an option, at least.)
 

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I thought all the t5.1 had drl's from factory.
Can a simple switch be put in place as a short term fix ?
From memory some of the early aftermarket lightbar drl's had issues with this and suppressors were sent out to these people to sort this problem.
So maybe some digging into this will be a long term fix for you .
 

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I thought all the t5.1 had drl's from factory.
I believe that's true, but I don't think they became mandatory in the UK until sometime in 2012.

My 2013 Kombi still has the coding option to turn off the DRLs - but it doesn't do anything (not that I care - I don't actually want to turn them off), so I think they altered the wiring at some point in 2012.
 

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Discussion Starter #20
Thanks for all your help and ideas. (y) I will go down the suppressor route to start with, but if that doesn’t work, I’ll wire up a simple switch somewhere under the dash on the drivers side to switch DRL on and off at will, because for the moment, I can’t think of anything else to do.

The weird part of all this is that these lights must have cost the previous owner hundreds, especially with painted interiors, and he also appeared to be serious about ICE, too (50w Genesis amp, uprated quad speakers, and an insane sub-woofer, that I’ve sold now, as I have no real need to sound like Motörhead Live on a regular basis...) Maybe he never wanted to listen to the radio??
 
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