wander627 Posted June 12, 2019 Report Share Posted June 12, 2019 So having a strange issue which my local garage has also been stumped by, it's an issue that's been there a few months but only recently getting round to sorting. the Radio on the car works perfectly when the car is unlocked and no key in the ignition. once you place the key in, still all is fine can find every radio station possible. As soon as the key is turned to the right (ignition on with all the dash lights) the radio becomes static, no reception at all. Turn the ignition off and the radio is perfect again, either ignition on or engine running, little to no radio whatsoever, just continuously scans. On a side note, there is a whine coming from what the garage has informed me is the alternator, pulley has been replaced in the past not too long ago, whine goes up and down with RPM but after 3k rpm the carnewal exhaust blocks it out but when in traffic or pulling away it whines away. could the two things be connected as in when the ignition is turned on does anything switch on in the alternator that can cause this interference? i've had the head unit out and everything looks absolutely fine on that side grounding looks all ok, etc. I have a LApower bluetooth module but i've completely removed this to be certain that wasn't causing issues. I know there's an amplifier in the A-Pillar, but if the radio works perfectly with the ignition off i assume that's not going to be the issue? could it be a bad diode in the alternator? or would that only reveal itself once the alternator was up and running with the engine? don't particularly feel like changing the alternator as guesswork any advice on where to look next would be greatly appreciated! cheers! Link to comment Share on other sites More sharing options...
Paul P Posted June 12, 2019 Report Share Posted June 12, 2019 Is it a standard head unit? Reason for asking is that I have heard that in some cases a seperate permanent live feed is required to the head - and in the process, sometimes things get wired up "unusually" - I can imane the power to the antenna amp is from the head unit, and if switched power to the head is mixed up with live then maybe it's getting turned off. Alternator (rectifier bit) really only deals with AC -> DC - failures in that area are typically charging issues, or battery drain even when the car is off. Is the whine mechanical (ie. it's physically making the noise) or electrical (you can hear it through the speakers (radio off and / or on)? All guesswork - but perhaps expose the antenna amp - check it's getting power at both ignition"off" and ignition "on" and work from there as far as FM reception goes. Link to comment Share on other sites More sharing options...
wander627 Posted June 12, 2019 Author Report Share Posted June 12, 2019 Hi Paul, thanks for the reply, so the head unit is completely standard PCM 2.1. other than the bluetooth module everything is standard. i've removed that bluetooth box, no difference. the whine is high pitch and more mechanical, as in its definitely coming from the unit itself, had the compartment off, listened with metal rod. had a suggestion once of removing the serpentine belt to test, did this before when engine was obviously dead cold, and no whine at all when the belt was off, only ran it for a matter 10 seconds but whine was gone. does the antenna amplifier receive current only when ignition is turned to on position? and which pillar will i find it in, drivers side or passengers side? thinking about this the windscreen was replaced last summer.... can't be sure that's when these issues started though. thanks! Link to comment Share on other sites More sharing options...
Rob™ Posted June 12, 2019 Report Share Posted June 12, 2019 An old Mini Cooper had a problem with the bluetooth module that distorted the sound - probably swapped out 95% of the sound system (head unit, some of the wiring, what else was back there...) before they figured it out. Luckily all done under warranty. Notice you've removed that though... Link to comment Share on other sites More sharing options...
wander627 Posted June 12, 2019 Author Report Share Posted June 12, 2019 yep, the bluetooth module was the only 'modification' and was truly hoping by removing it all would be solved... there's a good chance the alternator is failing and my antenna is screwed and this whole thing is two separate issues... alternator failing on a car with 107k wouldn't surprise me, especially as i believe it's the original. only had the car since 90k and loved every mile since, including the last few whining thousand! Link to comment Share on other sites More sharing options...
Paul P Posted June 12, 2019 Report Share Posted June 12, 2019 9 minutes ago, wander627 said: Hi Paul, thanks for the reply, so the head unit is completely standard PCM 2.1. other than the bluetooth module everything is standard. i've removed that bluetooth box, no difference. the whine is high pitch and more mechanical, as in its definitely coming from the unit itself, had the compartment off, listened with metal rod. had a suggestion once of removing the serpentine belt to test, did this before when engine was obviously dead cold, and no whine at all when the belt was off, only ran it for a matter 10 seconds but whine was gone. does the antenna amplifier receive current only when ignition is turned to on position? and which pillar will i find it in, drivers side or passengers side? thinking about this the windscreen was replaced last summer.... can't be sure that's when these issues started though. thanks! Antenna amp is in the left hand side a pillar - they have been known to go bad - but are cheap - actual antenna is in the windscreen - so a replacement screen may be part of the issue - not sure how they are connected - but you can "see" the antenna in the glass. As far as I know - the head unit drives the power to the amplifier - if its standard head and wiring then its possibly a red herrings - but I remember that the head to amp connector was in a non standard pin config - and some aftermarket harness adapters picked up the wrong connection - not a factor in this case Link to comment Share on other sites More sharing options...
wander627 Posted June 12, 2019 Author Report Share Posted June 12, 2019 thanks for the info, i'll remove the passenger side pillar tomorrow and see if i can see anything not quite right, it's strange how it works perfectly when the ignition is not on... maybe the amplifier kicks in when the ignition is switch to 'on' position and there's a lose connection there that's causing havoc... Link to comment Share on other sites More sharing options...
wander627 Posted June 17, 2019 Author Report Share Posted June 17, 2019 just thought i'd post to resolve this. I seem to have got to the bottom of the electrical side of things for the radio. removed passenger A pillar, checked amplifier, everything all ok, removed radio once again. still good. as a last minute guess before it got dark i thought i'd check the fuse box. opened up the panel and noticed a wire with a piggyback fuse.... about 6 months again i had a dash cam hard wired into the car. the dash cam works fine. checked the connection and as soon as I removed the black ground wire from the nut it was mounted to the radio came back clearly... so the ground wire which was being used for the dashcam was causing this issue. what's strange is that it all worked fine when it was installed, after doing some research i've noticed the hardwire kit appears to be an ebay clone... not an official nextbase one. i've read elsewhere these cheaper ebay ones can cause all sorts of interference issues. i tried multiple grounding points. same issue. so, genuine Nextbase dash cam hardwire kit on order from amazon, replace it over and should be good to go again! Still got that Alternator whine though.... but i do believe it might just be on it's way out... thanks for the help! Link to comment Share on other sites More sharing options...
Paul P Posted June 17, 2019 Report Share Posted June 17, 2019 Good to get to the bottom of this. I notice the nextbase kit Has one of those carbon clip on choke things. Perhaps that’s the difference re electrical noise. Link to comment Share on other sites More sharing options...
red rocket Posted June 17, 2019 Report Share Posted June 17, 2019 I've got the genuine Nextbase hardwire kits in both my cars and no interference so hopefully the clip on thingy should solve the problem. Link to comment Share on other sites More sharing options...
Kjb1 Posted June 17, 2019 Report Share Posted June 17, 2019 Whilst reading from start, I was going to comment saying check all your earths!! Good job! Link to comment Share on other sites More sharing options...
DaveEFI Posted June 18, 2019 Report Share Posted June 18, 2019 The noise from the alternator is likely a red herring. With no signal to the radio from the aerial, all sorts of rubbish may make itself heard. I'd first check there is power to the aerial head amp under all key positions. And then that the permanently live feed to the radio is present at all times, and the switched one in all relevant key positions. Link to comment Share on other sites More sharing options...
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