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I have an old Impreza 2002. Stereo Receiver died. I bought an inexpensive Boss Receiver from Amazon and also bought a Scosche Wiring Harness that fit my car. Put it in and not getting sound from front left speaker (double checked the wiring connection). I know it could be the speaker but prefer not to pull door panel off. I have an inexpensive radio shack multi-meter. Can I use it to track down my problem before attacking my door?
Thanks Peter
If the other speakers are working and you've confirmed a valid connection to the speaker in question (at the harness), then it is likely either the speaker is dead or the wiring between the harness and the speaker is interrupted somewhere. In which case the best place to use a multimeter would be at the speaker itself.
It is a simple task to remove the door panel on an Impreza. You will need to remove a couple screws on the door handle and then proceed to pull the door panel out of a series of clips along the outer edge (this is what you would do for an 02 WRX, I am sure the instructions would be similar for a base Impreza).
If you're up for removing the door panel; once removed, you would first notice the physical appearance of the speaker. If it's cracked or ripped, it's most likely blown. To be sure, you could do a resistance test with the multimeter. Set the multimeter to the resistance setting to measure the speakers impedance. Usually you would see a setting of 20Ω which is in the range of what we are looking for. Hook up the probes to the positive and negative terminals of the speaker and observe the reading. If it is zero, your speaker is dead. See a detailed tutorial here.
If you are getting a decent reading (which varies depending on your speaker's impedance), then you know your speaker is fine and the wiring must be faulty somewhere. To be sure, change the setting on the multimeter to volts in the range of 12V (usually the 20V setting). Turn your stereo on so there is power and connect the probes to the positive and negative wires at the back of the speakers. If you are not getting a reading of ~12V, then you have narrowed the problem down to faulty wiring. This could be fixed by re-running a new wire from the speaker to harness, which could be a PITA if you're not into it.
Unfortunately there isn't a lot you can do without taking the door panel off, and checking the speaker's condition directly. You can however check if the speaker is getting 12 volts from your wiring harness. Here is a link to what hopefully looks like your wiring harness in your Impreza.
Take the multimeter, make sure the cords are placed in V and COM and on DC Voltage with the pointer set to 20. Place the red cord on pin 3 from the picture, and the black cord on pin 9. This should give you a reading of 12V-13V. If this is zero, its possible you've blown a fuse when the new stereo was put in or the speaker was cranked up too high. Normally however, both speakers wouldn't be working and possibly even the stereo if this was the case, but I don't know your vehicle's setup.
Else if it is reading 12V, you will need to pull the speaker out, it may have rusted or the terminals lost connection or even simply blown which you can test with a 9V battery by doing the pop test.
Hope this helps!
