2007 wm caprice, stereo problem

I own a 2007 WM Caprice. Recently the 12v socket in the boot was bumped, it created a spark,ever since this happened the stereo has developed an intermittent problem, the problem is that the power to the stereo will randomly cut out, if I turn the car completely off for a minute or the stereo will turn back on and work normally until the next time it cuts out, what I need help with is "where to start" with fault finding this problem. I have a certificate in electronics so I do have a good understanding of electronics, I am just not sure the best place to start looking for a problem like this.

Thanks for all your help

If you have another car radio(nothing fancy needed) to test with, you can install it to rule out the wiring in the car as being the issue.

If it's definitely the car radio, it could be almost anything but I would open the radio and check for burnt traces on the board or bulging capacitors. Depending on what the car radio is worth, you may consider just buying a new one.

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Thanks shortcircuit it is actually the stock stereo, probably worth at least a couple K as it is a 6 disc stacker plus it runs two head rest screens and is also a navigator, so replacement is out of the question and also testing with another unit cant be done as it is the new type of car stereo that is specifically built for the car, I need to be able to find the fault. Thanks for the reply

what do you mean when you say the 12v socket in the boot was bumped? i dont understand this at all. what socket? what boot? are you talking about the door boot where the wires run into the door or are you talking about the main harness boot that goes through the firewall into the engine compartment? what do you mean by "bumped"? also what exactly were you trying to do when this happened? if you can explain these things more completely then i can help you fix it.

maybe its just my fault for not understanding you but keep in mind that most of us are on the other side of the ocean and certain words just dont translate well

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soundnsecurity wrote:

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what do you mean when you say the 12v socket in the boot was bumped? i dont understand this at all. what socket? what boot? are you talking about the door boot where the wires run into the door or are you talking about the main harness boot that goes through the firewall into the engine compartment? what do you mean by "bumped"? also what exactly were you trying to do when this happened? if you can explain these things more completely then i can help you fix it.

maybe its just my fault for not understanding you but keep in mind that most of us are on the other side of the ocean and certain words just dont translate well

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LOL Sorry I mean the 12v cigaret socket in the TRUNK, we were putting our baby carriage into the trunk and it got knocked, and sparked, the problem has been there ever since.

ok, now we are getting somewhere. does the socket still work? i would start by investigating why the socket sparked to begin with, are the wires exposed and make sure there isnt something like a coin or metal object stuck inside the socket. also you should inspect any other wires that are in the area of the socket because maybe there is some damaged wiring close to the socket that made contact and sparked.

if you dont find anything that is obviously damaged then i would turn the car/radio on and start shaking any wires and connectors you can find in the area around the socket. look for any changes to the radio while you wiggle the wires and plugs. this will hopefully point you in the right direction. if you can force the radio to turn off just by playing with the wires then you know that the problem is not with the radio.

also, sometimes the audio system and 12v sockets will share a common fuse so you should make sure you check every fuse in the car and make sure every fuse is tight and in the right spot on the fuse box.

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soundnsecurity wrote:

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ok, now we are getting somewhere. does the socket still work? i would start by investigating why the socket sparked to begin with, are the wires exposed and make sure there isnt something like a coin or metal object stuck inside the socket. also you should inspect any other wires that are in the area of the socket because maybe there is some damaged wiring close to the socket that made contact and sparked.

if you dont find anything that is obviously damaged then i would turn the car/radio on and start shaking any wires and connectors you can find in the area around the socket. look for any changes to the radio while you wiggle the wires and plugs. this will hopefully point you in the right direction. if you can force the radio to turn off just by playing with the wires then you know that the problem is not with the radio.

also, sometimes the audio system and 12v sockets will share a common fuse so you should make sure you check every fuse in the car and make sure every fuse is tight and in the right spot on the fuse box.

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hi there I did check the socket and it is working I have checked the wiring to the socket and it is all fine, I am pretty sure the metal edge of the socket has bumped up against the body of the car. I have also wiggled the socket and the wiring with the stereo on to see if any thing is lose but nothing happens, I will check all the fuses and get back to you on that, thank you so much for your help.

it shouldnt matter if the outside of the socket touches because the outside should be grounded anyway( unless its different in Australia). only the center on the inside should be live, this is why i thought maybe there could be some exposed wires touching the socket somewhere.

chances are this has nothing to do with that 12v socket

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I agree with the above, however most times if you draw a spark, a fuse somewhere will blow.  Have you checked all your fuses?  It is also possible that a fuse can blow but not violently enough to break the circuit completely and "look" blown.  You need to check them with a meter.  I've also seen fuses blow but still make contact until they heat up due to current flowing through the circuit, then they open and turn things off, then when they cool back down they close again, like a switch.  This can be super frustrating to try and troubleshoot so in these cases a whole-sale fuse swap in the effected circuit is often needed.  It is also possible that whatever transient you caused blew something inside the head unit instead of a fuse, so the issue is in the head and you'll never find it without pulling the unit.  Intermittent problems are the worst, but most of the time they are heat related and they occur inside electronic equipment, not on the power side.  I'd pull the head and get it bench tested.

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Yes it does seem to be heat related, like its overloading, when it does turn off, sometimes it will come back on after a couple of seconds then go back off again, which actually seems more like bad connection but what really sets me back is that also when it turns back on I can guarantee that it will turn back on if it switch the car off for a couple of minutes, which seems more like a heat related problem or an overload, thanks every one so much for all the help you are giving me I really appreciate it. Today I will check every fuse with my meter, then if I don't find any blown fuses I will have to remove the unit and bench test it. I will come back on here and post my results later.

Thanks

happileej wrote:

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Yes it does seem to be heat related, like its overloading, when it does turn off, sometimes it will come back on after a couple of seconds then go back off again, which actually seems more like bad connection but what really sets me back is that also when it turns back on I can guarantee that it will turn back on if it switch the car off for a couple of minutes, which seems more like a heat related problem or an overload, thanks every one so much for all the help you are giving me I really appreciate it. Today I will check every fuse with my meter, then if I don't find any blown fuses I will have to remove the unit and bench test it. I will come back on here and post my results later.

Thanks

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Sorry I mean when it turns back off I can guarantee that it will turn back on if it switch the car off for a couple of minutes

now that i think of it it could be a blown or shorted speaker too. maybe the speaker terminal is making contact with sheet metal sometimes and it forces the radio into protect mode.

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I checked all fuses today, none are blown. I did notice while I was checking the fuses though that the back of the 12v socket easily can short out as the two connecting terminals are exposed and also the socket does not sit tight as the clip is broken, so I am thinking that maybe when the car bumps around the socket moves into a position that it is shorting out and then the stereo might be forced to switch off, so I have covered all the exposed terminals with electrical tape, I'll drive the car for a couple of days and see if that fixes the problem, I will post the results of that.

Thanks again