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The headunit in my Amazon keeps cutting out, and when switched back on again, has lost the memory settings. This is only a recent problem - the entire stereo was fitted about two years ago (the headunit was bought new at that time), and I have checked all the wiring (it runs directly off the main fusebox, and is wired correctly for permanent & ignition lives) but there is no visible damage.
It appears to happen only when the heater is on, so wondering if this is the internal amp tripping some kind of failsafe? Amazon heaters are rather volcanic, but as far as I can see, the heater ducting isn't damaged, so it's not as if there is now suddenly now a blast of hot air being aimed at the stereo. Previously having it on full blast didn't cause any problems, even though the main front outlet is below and slightly forward of where it is mounted.
Does anyone have any idea what the problem may be? Is it a case of using an air can to blow out the cooling vents for the amp on the headunit (as with the heatsink on a laptop), or this due to the unit being on its last legs?
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it could be the heat the cd player in some of our lorrys at work seem to cut out when I have the heter in to high and the vent is right on top of it and its a brand new lorry
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Last Edit: Feb 2, 2012 13:16:23 GMT by stretch
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I agree that the heat is certainly a factor, but over the last two winters it was fine, so a new factor is now contributing to the problem.
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Last Edit: Feb 2, 2012 14:45:47 GMT by Paul H
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Does the stereo share an earth with the heater fan?
Do you have a multimeter? Sounds like the power drawn by the heater blower is pulling the voltage on the input for the stereo down and causing it to trip. Either by causing the earth to float high, or dragging the overall voltage down. Pop the stereo out, put the heater blower on full bore and turn the music up. With the engine running, you shouldn't see any less than 12.5v or so on the input of the stereo (check both the memory, and the ignition feeds) and use the earth wire to the stereo as earth.
The stereo will probably work fine down to about 10.5v before it turns off.
If you get a low voltage, you need to work out whether it's a weak 12v feed, or a weak earth. Do this by moving your negative probe to some exposed metalwork in the car, but with the positive probe still measuring from the stereo power feed.
If the voltage is still low, you have a weak 12v feed. If it measures 13v+, then the earth is poor.
Also check the voltage across the battery, you could have something like a weak alternator that's struggling to keep up.
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Sounds to me like a duff connection somewhere - either internally or in the wiring. As Cobblers says go over all the connections carefully with a multimeter. Try and pull connectors off to see if any are loose.
One thing you could do is run cables (2 x live and earth), temporary, direct from the battery and see if the symptoms go away. If they do then disconnect each of the temporary connections until the problem reoccurs which would highlight which permanent part of the wiring is faulty.
Paul h
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Cheers Cobblers - will look into that. IIRC, the earth is somewhere related to the heater, so what you say all makes a lot of sense.
However I'd be surprised if it's the alternator, as when that died this time last year, everything still worked fine. It was then reconditioned & all worked fine, despite only being 35A. Could a dying battery cause the problems you describe? The current one is at least 5 years old....
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Maybe it's not even faulty - The heater blower motor will probably draw around 15 amps. If the headlights are on, that's another 12.5. Add in a couple for the coil and you've only got 5 amps left to play with. The stereo, on loud with 4 speakers attached will draw something like 5 amps on average.
There's a chance you're just pushing the alternator to the limit, and a weak battery is slowly going flat enough to let the stereo click off. The headlights would slowly dim, so you might not notice it.
My money is still on a poor earth, or the main +12v feed from the battery to the fuse box not being man enough and dropping to about 8v when the heater blower is on.
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Sounds to me like a duff connection somewhere - either internally or in the wiring. As Cobblers says go over all the connections carefully with a multimeter. Try and pull connectors off to see if any are loose. One thing you could do is run cables (2 x live and earth), temporary, direct from the battery and see if the symptoms go away. If they do then disconnect each of the temporary connections until the problem reoccurs which would highlight which permanent part of the wiring is faulty. Paul h Only just seen this - will look into that too. Cheers  |
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Maybe it's not even faulty - The heater blower motor will probably draw around 15 amps. If the headlights are on, that's another 12.5. Add in a couple for the coil and you've only got 5 amps left to play with. The stereo, on loud with 4 speakers attached will draw something like 5 amps on average. There's a chance you're just pushing the alternator to the limit, and a weak battery is slowly going flat enough to let the stereo click off. The headlights would slowly dim, so you might not notice it. My money is still on a poor earth, or the main +12v feed from the battery to the fuse box not being man enough and dropping to about 8v when the heater blower is on. My drive to work each morning is with the lights off and in the evening going home with them on, and I can't see any difference in the symptoms. Even with the unit off, but still live (i.e. keeping its memory), it will still go off if the heater is on too high, as when I put the face on, I find it has lost the settings. I'd certainly agree with you that the earth / battery sound like the most obvious suspects. |
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Last Edit: Feb 2, 2012 16:15:39 GMT by Paul H
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I'd say you need a new head unit, aftermacket stuff just not as good as original equipment for longivity, had a head unit in one car which after a couple of years would turn it's self on/off randomly, first thought was who's that tosser with the music on at 3 in the morning!!
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Cheers guys for the advice - much appreciated & as a result, I *think* it's fixed I've moved the earthing point, and so far it's now working as it should, even with the heater on full blast (which even in this weather, means I need to open a window.....)  ;D |
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I'd say you need a new head unit Wow, what an awesome diagnosis. Next time I get a flat tyre, please can you diagnose that I need a new car? [edit] Glad you got it sorted Paul, electrickery is one of those things that can cause a lot of frustration yet can often be a simple fix. Enjoy your tunes *and* your heat ;D [/edit] |
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Feb 12, 2012 20:33:21 GMT
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I'd say you need a new head unit, aftermacket stuff just not as good as original equipment for longivity, No, cheap aftermarket stuff is no good. Proper headunits cost money. I've got an Alpine CD9830R which I'd put money on being better than most OEM stuff. |
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;D
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