Silent Radio.... (1 Viewer)

Mar 26, 2018
440
1,366
Ormskilrk
Funster No
53,013
MH
Swift Voyager 685FB
This has me confused.....

If I turn the radio on and don't drive the MH I get sound.
If I turn the radio on and then drive the MH the sound eventually stops coming out of the rear speakers. Turning the radio on and off now will mean I get no sound at all.
If I drive for a bit and then turn the radio on I get no sound.

Thinking I had a duff radio that was overheating when the engine warmed up I replaced it with a satnav/radio combi.

This does exactly the same!

So.....is there an amplifier between the radio connection and the speakers?

The wiring comes out of my radio and goes to a double connector. One connector is the power and earths. The other is 8 cables for the 4 speakers. I could understand one cable having problems and me losing one speaker but I get no sound from any of the four once the cab has warmed up. Works fine when cold.

Heeeeeeelp.
 
Jan 19, 2014
9,435
24,928
Derbyshire
Funster No
29,757
MH
Elddis Accordo 105
Exp
since 2014
This has me confused.....

If I turn the radio on and don't drive the MH I get sound.
If I turn the radio on and then drive the MH the sound eventually stops coming out of the rear speakers. Turning the radio on and off now will mean I get no sound at all.
If I drive for a bit and then turn the radio on I get no sound.

Thinking I had a duff radio that was overheating when the engine warmed up I replaced it with a satnav/radio combi.

This does exactly the same!

So.....is there an amplifier between the radio connection and the speakers?

The wiring comes out of my radio and goes to a double connector. One connector is the power and earths. The other is 8 cables for the 4 speakers. I could understand one cable having problems and me losing one speaker but I get no sound from any of the four once the cab has warmed up. Works fine when cold.

Heeeeeeelp.
Have you got a multimeter?

The resistances of the wires will tell you what they're connected to.
 
OP
OP
Neil Bedwin
Mar 26, 2018
440
1,366
Ormskilrk
Funster No
53,013
MH
Swift Voyager 685FB
I fitted the new satnav/radio unit so I know what the wires are connected to. They are all connected correctly and work when the engine is cold. I was just wondering if there was a built in amp between the radio and the speakers and that could be overheating and causing my loss of sound.
 
Jan 19, 2014
9,435
24,928
Derbyshire
Funster No
29,757
MH
Elddis Accordo 105
Exp
since 2014
I fitted the new satnav/radio unit so I know what the wires are connected to. They are all connected correctly and work when the engine is cold. I was just wondering if there was a built in amp between the radio and the speakers and that could be overheating and causing my loss of sound.
Yes, I meant if you measure the resistance on the paired speaker wires and they are connected directly to a speaker, the resistance will be low ie less than 100ohms.
If they go to an amplifier input it will be thousands of ohms (y)
 

Gellyneck

LIFE MEMBER
Jun 5, 2014
9,509
19,073
Scotland
Funster No
31,836
MH
C Class
Exp
More than toes wet now!
Does the radio display stay on when you loose sound?
If so, it possibly the head unit going into protect mode. This is, generally, caused by overheating, an intermittent internal fault or and power \ speaker wiring faults.
Check to see if the is a break in the sleeving of the wiring (or loose connection).
Try connecting "spare" speakers (if you've got any) directly to the back of the head unit and see if fault reoccurs.
If not, try disconnecting individual speakers and check for reoccurance.
A bit of a process of elimination.

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Neil Bedwin
Mar 26, 2018
440
1,366
Ormskilrk
Funster No
53,013
MH
Swift Voyager 685FB
Yep the radio stays on and the satnav works but no sound comes out. I replaced the original radio because of this problem so I can believe the problem is within the unit. It's hard to believe I would have wiring issues to 4 speakers, all of which have a +ve and a -ve connection. This is why I wondered if there was an amp between the radio speaker connections and the speakers. No wiring diag I find shows one though.
I suppose my next step is to warm everything up until it stops working and then jiggle all the wires.
 

hilldweller

LIFE MEMBER
Dec 5, 2008
605
36,109
Macclesfield
Funster No
5,089
MH
Zilch Mk1
Exp
From Aug 2007
I suppose my next step is to.................

Get hold of a priest specialising in exorcisms. It's the craziest fault I've ever heard.

Tiny possibility - do modern radios have a mute input ? Anything labelled mute on your connections ?
 

philb 1

Free Member
Dec 21, 2014
22
10
North Yorkshire, UK
Funster No
34,530
MH
Bailey Autograph 745
Exp
2012
Could it be the OHMS on the speakers are they 4 or are they 8 OHMS what does the radio Manuel say they should be would this be the answer ?
 

Misterg

Free Member
Dec 8, 2017
221
213
N Wales
Funster No
51,599
MH
Self build PVC
It's hard to believe I would have wiring issues to 4 speakers, all of which have a +ve and a -ve connection.

Don't know about the radio that you've fitted, but the OEM Uconnect radio on our 2018 Relay mutes the speakers if it detects a fault & won't turn them on again until it's been completely switched off.
 

Baileysbus

Free Member
Aug 2, 2016
731
2,414
Fife
Funster No
44,376
Exp
Start of 2016
It’s probably designed to switch off when Jeremy Vine comes on the radio. What time of day did you test it?;)

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Neil Bedwin
Mar 26, 2018
440
1,366
Ormskilrk
Funster No
53,013
MH
Swift Voyager 685FB
Right!

Had another look. I have the 8 speaker connectors on one connector block. On the other connector I have permanent +ve, switched +ve, earth, a dimmer connection and another. The another connection seems to take power from the Hab side of the MH and feed it to the Fiat wiring harness! Looking at the wiring diag for an ISO connector it is plugged into the Phone Mute connection!!

So I have to wonder why I have 12v being fed into the phone mute connection of the Fiat from my leisure battery?

I could understand 12v being fed to the radio from the leisure battery so it works when the engine is off but don't understand it going to the phone mute connection.

I have disconnected this wire and everything still appears to work. If I get time later I will take the MH for a run and see what happens......
 
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OP
Neil Bedwin
Mar 26, 2018
440
1,366
Ormskilrk
Funster No
53,013
MH
Swift Voyager 685FB
Fixed it!

As most intermittent problems go this one became permanent so I had to have a proper go at fixing it.

It was discovered that unplugging the speakers at the ISO connector sometimes made the sound come back. So I took all the pins out of the connector and put them back in one pair at a time. I found that plugging the front left in caused all the sound to stop. Assuming I would find the speaker wires shorted in the rubber cableway between the door and wing I stripped off the insulation tape but no bare or broken wires were found. I ran two new cables from the connector to the speaker and it worked. I plugged the original -ve into into the connector and with a new +ve it still worked. I was just about to run the new wire through the the dash to the door when I heard a click from the tweeter in the A pillar. A couple of screws later and it turned out the tweeter is connected to the same wires as the door speaker.....only it was loose in it's housing and the metal strip on it's side was touching the bodywork! A bit of insulation tape and clicking it back into place later and everything was good to go.

It's taken a long time to fix but only because I ran out of round tuits.....
 
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