Speaker issue diagnosis help

[Jake_rorx7]

A few months ago, my two front speakers suddenly stopped working within a day of each other. One went, then the other. Never got around to sorting it until now...

Car audio is not something I am good at, has anyone got any tips for diagnosing the issue? I don't really have a clue where to start. Both front speakers have continuity (across the speaker). What sort of resistance should I be looking for? How can I diagnose the headunit output and see if the headunit is the issue?

Both rear speakers work fine, headunit works normally other than the front two speakers.

Headunit is Alpine CDE-296BT

 

[Satoshi-FD3]

There are a few reasons that sound can fail, speaker short, output I/C blown on the headunits front output, loose connections on speaker terminal or wiring harness at the rear of the unit etc.

1) Check Fader settings on headunit to make sure no one has faded output to the rear only.
2) Pull the headunit out and check the wiring behind.
3) If it's been installed properly then you should have a brown ISO connector which is for audio output, disconnect this and using your multimeter check each colour matched pair for 4 Ohms resistance. (Front's are White & Grey) Check across them,

If the speakers are connected and reading 4 Ohms then chances are if it's not the fader you need a headunit repair.

 

[Jake_rorx7]

There are a few reasons that sound can fail, speaker short, output I/C blown on the headunits front output, loose connections on speaker terminal or wiring harness at the rear of the unit etc.

1) Check Fader settings on headunit to make sure no one has faded output to the rear only.
2) Pull the headunit out and check the wiring behind.
3) If it's been installed properly then you should have a brown ISO connector which is for audio output, disconnect this and using your multimeter check each colour matched pair for 4 Ohms resistance. (Front's are White & Grey) Check across them,

If the speakers are connected and reading 4 Ohms then chances are if it's not the fader you need a headunit repair.

Cheers for the reply

1) reset headunit fully and checked each setting multiple times in my effort to fix it
2) wiring seems in tact
3) Havent checked this one yet, 4 ohms on the wiring/speaker side, or the headunit side?

 

[JoeLanger]

Plug the rears into the fronts. Where the fronts should go. If they work then Speakers are broke. If they don't work then something wrong somewhere else

 

[Nite_Shayde]

Re. 3), resistance across each speaker (while disconnected from headunit)

 

[Jake_rorx7]

Alrighty, so first I'll check resistance across speakers tonight from the headunit connector. If they are ok, then wire fronts to backs and vice versa, see if anything changes...

If the speakers swap (if fronts work) then its a headunit issue. If it doesnt swap (backs still only one working) then its a speaker issue...

Thanks, will let you know what happens!

 

[4packet]

If both speakers failed within a day of each other then seems unlikely to be a speaker issue. My money would be on a poor connection at one of the plugs behind the stereo. Always difficult to stuff the harness neatly, without causing strain whilst fitting the stereo. I'd pull the stereo out and test it while manipulating the connectors. Tip if you want to identify or verify the speakers/circuit without being connected to the stereo: use a small battery (AA or similar). Short the pair of speaker wires and the speaker will crackle.

 

[Jake_rorx7]

Alright got a look on my lunchbreak...

Removed headunit and disconected

Probed rear two speaker pairs. 4 ohms across each

Probed front two speaker pairs. no connection at all. Which is weird because I remember when I had the door cards off and probed across the speakers directly there was at least continuity, even though I didnt test for resistance. Going further, there are 3 plugs behind the headunit that the speaker wire travels across.. So I probed from the headunit plug to the start of the OEM harness - good continuity.

I was going to try to connect the headunit up and then wiggle the harness to see if i can reestablish some sort of signal to the speakers, but I managed to pop the cigar fuse (a power wire in the oem harness got pinched and cut, then it managed to touch the frame) and had to fix that so ran out of time for now.

Will have a better investiigation of the wiring at the weekend, will measure resistance across the speaker directly, then try and find what section of wire has a continuity break. Might have to run some fresh, better quality wire to the speakers.

 

[Damz]

Hopefully the wiring behind the stereo won't be a complete disaster like I've had on imports in general.

Spent a good few hours trying to work out which wire linked to which speaker etc.

 

[Jake_rorx7]

Finally got around to the job after forgetting about it... Got a long 7 hour coastal cruise in a few weeks and could really do with some good music on the way...

In the end it was corrosion near the crimp connectors on the speaker. Not a lot - to the casual observer they look fine. But they are wires that came with the speaker itself, so thin tin wires and tin crimps. They corroded not on the terminal but up the wire, through water travelling up the wire by capillary action I suppose.

Previously, to fit the slightly deeper drivers, I modified the speaker housings by chopping various bits out. Turns out this housing serves a pretty good purpose of keeping water off the speaker connections!! Who would have thought?

Replaced the wire with high quality copper speaker cable and brass crimps, along with some lovely hoods that should do a better job of keeping water off of the metal contact. I've finally got my front speakers back!