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Discussion Starter #1
Good day to you if you've happened to stumble across this..your help/advice would be much appreciated. I have a 2006 Vogue...a lovely car with no issues whatsoever except for the **** head unit, it's driving me nuts. Problem started 3 years ago when I had the gearbox replaced..radio not working on the way home (power but no sound), but it seemed to sort itself out by the next morning. About a year later same thing..no radio. I pushed and prodded a few wires at the back of the car (please see photo) but had no idea what I was doing so didn't expect much, however it started working later that day. Since then it seems to work as and when it feels like. Common sense would suggest a bad connection someplace but I've no idea where to begin. I'm not too bad on the spanners but I don't want to mess things up completely and start taking a load of electrical stuff apart unless I have to. As a side issue, and again I've no idea if it's in anyway related, the satnav doesn't have a clue where it is anymore..when I fire it up.it can start me off anywhere between Munich and Glasgow, but on a plus note the reversing camera has started to work for the first time!!! I can live without the camera and get by with a cheap stick-on satnav...but I miss my radio.
283890
 

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2010-2012 Range Rover MkIII / L322
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Does the radio failure coincide with a rainfall event?

You may have water leaking into that area (the nav DVD player's casing appears to have quite a lot of surface corrosion). Check ALL the connectors on the side of the vertically mounted amplifier, especially the lower connector plugs including the two thicker cables (red +12v and black or brown -12v) which power the amp (usually insulated within a green plastic connector plug housing).

That black plastic box on top of the Nav DVD player is your bluetooth module.

Does your bluetooth work OK?

The two white wrapped "cables" plugged in to the side of the BT module are part of your MOST circuit. These are fiber optic cables passing light along the circuit, not voltage.

MOST is a "looped" circuit, requiring a fiber optic LIGHT signal (red) to be relayed from module to module without interruption into, and exiting from, each ICE related module within the vehicle for your head unit to work correctly.

An interruption to the MOST loop creates a "break" in the signaling to the head unit (search multiple threads on flashing red lights on the on/off button).

Because the MOST is looped there is the possibility that:
a) there's a bad module not passing the signal onwards to the next downline module;
b) there's a break in the MOST loop cabling between modules;
c) the MOST light signal generator is intermittently failing.

Here's a beginning on how to check for a)

Given that you can now identify the BT module, unclip the MOST connector at the BT unit and turn the ignition to position 2 with the stereo "on".

Go back to the now disconnected MOST connector and look into the very ends of the two white cables.

One of the two cable's ends should appear to glow red while looking at the tip. It may help to do this at dusk or in a low light condition.

You're not going to see a Dr Evil type laser brightness but you should at least be able to determine that a red glow is evident within the tip of ONE of the two MOST cables.

If you do see a red glow, that may be good news - given that a failed BT module is a very common occurrence.

You now need to try and "fool" the MOST circuit by bypassing the [potentially bad] BT module by connecting the two MOST cable's tips end to end in order to allow the red light to "pass" along the MOST cabling to the next downline module in the loop. DO NOT kink the fiber optic cables.

If your stereo now works, chances are your BT module is the problem and you can either replace it (I wouldn't waste the money but it's your car) or more permanently bypass it.

There are already plenty of threads/you-tube videos explaining how to do that etc.


If it doesn't work by bypassing the BT module, but you do detect a red glow at the BT module, reconnect the MOST connector into the BT unit and proceed along the MOST cable line to the next module, repeating the bypass exercise until you locate the break in the MOST circuit.

Rob
 

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Discussion Starter #3
Thanks very much for taking the trouble to explain it like that, Rob....I'll certainly have a go at it this afternoon now I know what to try. You could well be right about the rainfall event..I live in Wales, we get a lot of the stuff here!
 

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I tried what you suggested with the BT unit Rob...there was a red light on one of the wires but it was pulsing regularly and not a constant light. Don't know if it's supposed to do that. Anyway, I joined the 2 wires as per the video but still no sound. ~I took the other 2 similar junctions apart and both have a single pulsing red light. I didn't actually try to join these other units in a similar fashion but that's a job for tomorrow. I'll take the amp out completely at the same time and check those connections you mentioned. One quick question if I can....what's this DSP display I've read about, should I have some kind of indication on the head unit if it's on or not? Can't say I've noticed even when the radio was working ok.
 

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The red light should be a steady signal, not a pulse.

The red light is generated from within the Integrated Head unit and is ported "out" through a lens which sends the light signal down through one of the fiber optic cables. The fiber optic cable pair connector (usually orange/white wrap) is plugged in to the side of the IH unit. Once the light source reaches the in port of the "end module" the light signal is then "returned" back through the MOST loop to the "input" lens of the MOST connector on the side of the Integrated Head unit.

The next thing to check is the output lens' red glow from the IH unit.

You'd check this by removing the horizontal trim panel underneath the glovebox (disconnect the footwell lamp connector as necessary) by undoing several torx type screws.

Look between the rear of the glovebox and the firewall and you'll see a vertically mounted module with a MOST connector and one or two electrical multiplug connectors (depending on the grade of stereo installed). You'll probably gain better access if you remove the two 8mm bolts which attach the thin horizontal metal mounting strip the lower portion of the IH sits on and let it drop down a few inches. Again, DO NOT kink the MOST cabling.

Disconnect the MOST connector, turn your ignition on to position 2 and [hopefully] observe a continuous red glow from one of the two lenses within the cavity on the IH unit (where you just disconnected the MOST connector). The other lens will be dormant (because it's awaiting the "return" light signal). You may find it easier to observe/detect a red glow from the connector's unplugged side by using a small mirror. If the red pulse is detected instead of a steady glow, I suspect you have an issue within your IH unit. Before replacing though, check the supply connections to the IH. There should be +12v and -12v between the two thicker wires in the electrical connector plug(s) (it should be obvious which two).

Here's a decent overview of how the system is supposed to "talk" to each component although it isn't exactly as fitted to your Vogue. Look for the Integrated Head unit component identification around the 1.05 mark. Yours should be the single "slim" IH unit.


Rob
 

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Discussion Starter #6
Thanks very much for the reply, Rob. Havn't got around to dismantling and ferreting about behind the glove box yet as there always seems to be something else to do, but thanks to your post I'll have a vague idea what I'm doing when I make a start. I'll have a go at most things if there's an outside chance I can fix 'em but to be honest, fibre optics and integrated head units could well be beyond the capabilities of this old guy. Whatever happened to twin carburettors and 8-track stereos? :)
 

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The IHU on an 06 is attached to the back of the touch screen in the dash. To get to it you have to pull the dash pad, the end vents and end covers of the dash. there are 6 phillips screws that hold the entire head uint/IHU into the dash accessible once you get the dash pad off. The IHU moved to a location above the glove box in the 07 model year and is much easier to get to thna in thr 05/06 model year trucks.
 

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Thanks very much for the reply Mark..and you too Rob, but I've come to the end of my patience with this car now. Young son borrowed it to go on a date on Friday night. No idea what he's done to it but he brought it back on Sat morning, still in the same clothes, and casually mentions that there's a funny noise coming from underneath! After a bit of grilling he admitted that he got lost and ended up driving through a flood on a country lane churning up stones and whatever else. I've had all the wheels off, can't see anything obvious other than a load of debris but it's the end of the road for the car as far as I'm concerned. It's off to auction this week, might get a couple of £1000 for it if I'm lucky. Shame really...perfect engine, new gearbox, air suspension, blah blah blah, but I'm done with lying on my back with spanners. On a plus note...the radio now works!!!!!! Cheers guys....
 

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Kids, that why mine had to buy their own vehicles. I like mine and don't enjoy fixing stuff other people break, only the stuff I break.
 
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