I started on this post here since I didn't have access to the full forum until now: https://www.fitfreak.net/forums/2nd-...r-speaker.html

Basically I have an aftermarket head unit. For some reason the drivers side rear speaker doesn't work and I can't take the car back to the place I had it installed because it's out of state.

I removed the head unit today and verified the wires. I plan on removing the door panel tomorrow and taking a look at the rear speaker. My question is how can I verify that power is actually running to the speaker once it's unplugged?

 

If you don't have some rather fancy electronic test equipment (like an oscilloscope), the easiest and surest way would be to connect up another speaker temporarily.

You might be able to verify it with a multimeter in the AC voltage range and a reasonable load of some sort—something between 4Ω and maybe 20Ω or so that can safely dissipate a little power, perhaps a 20W or so 12V light bulb. (The amplifier might act rather strangely or turn itself off when presented with no load.) Loud music with strong bass would be best for this, and don't expect to see more than a couple of volts or so. Seeing some voltage at the speaker terminals would indicate that something good is going on, and the speaker is quite possibly at fault; not being able to measure it, on the other hand, is less conclusive.

If you have a meter, it would not be a bad idea to check for any DC voltage across the speaker outputs while the audio is quiet while you're checking things. There should be none at all, or at the most a few millivolts. If there's anything much, that indicates a problem with the radio that could potentially be causing speaker damage.

If you determine that there seems to be no signal at the door, I'd suggest checking at the output from the radio if you can manage access to that connection while things are still otherwise plugged in. That would show whether the fault lies with the radio or with a wiring problem in the car (or conceivably both, if the radio design cut corners on the output protection circuitry).

 

1st thing I would do is pull the aftermarket head out of its sleeve and swap the solid purple and solid gray wires to see if you lose the rear left door and rear right works now. Involves no pulling of door cards. This will tell you if your head unit is the culprit. Another thing to try is pulling the wires at the head purple/purple back and using a 9v battery touch the solid purple(RR+) to purple and purple/black to (RR-) and listen for a popping noise. Guess I should clarify. The leads coming from the radio will be the standard colors and where they connect to the plug. Hopefully the shop didn't cut the factory plug out and go wire to wire.

 

Ya that's a good idea, and thanks for the info. I thought there was some weird proprietary plug that was inserted into the back of the speaker.

 

Great idea...I may do that. I've attached pics of the wiring harnesses but my colors don't match what you've listed unless I have the harnesses mixed up. Where I have purple wires is the harness plugged directly into the head unit. My guess was this was the non-Honda harness used by the shop. Please correct me if I'm wrong.

I ended up using this chart instead which seemed to match more closely. 2010 Honda Fit Car Stereo Wiring Diagram

Top View:


Honda Harness


non-Honda Harness (Drivers side rear speaker is on the bottom row I think)

 

Unplug harness from the back of the head. then strip a little of the purple and purple&black sheathing and put a 9v battery post to the bare wires. Solid purple to the (+) post and purple/black to the (-). The speaker should make a popping sound, if it does not ensure the battery has some juice by putting to your tongue. If it sparks its good and you have a wiring issue to the door. If it does pop, then its the head unit more than likely. To test this cut the gray, gray/black, purple and purple/black wires and swap the ends coming from the head unit to the wires going in to connector. make sense? The solid Gray to the solid purple, the gray/black to purple/black. If you have sound at right door and not at left door then its the head unit. Wish I lived closer to you as it would take less time to drop by and do this then explain it?!

 

I think I've got it. So why would it "pop"? Is it the way the current travels, like pulsing?

Also, Ohio is much closer than Oregon which is where I was before. Come on over!

 

the 9v charge from the battery is just enough to move the magnet enough to make it 'pop' even though the speakers are designed for a 12v system. Don't hold it very long. Just touch and listen for the pop. It's an 'old school' test. Your rear speakers are simple mid-range paper cones so this 9v test will not ruin your tweeters.

 

should i disconnect the battery, or will i be alright? sorry if these are noob questions but....i'm a noob.

 

Disconnecting the battery isn't a bad idea but you'll want to unplug the connector to the back of the head unit before you start messing with the wiring and the 9v battery.