I have an Impreza 2002. Stereo Receiver died. I bought an inexpensive Boss Receiver from Amazon and also bought a Scosche Wiring Harness. Put it in but 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?  

Did the old stereo actually die? Was it not able to turn on, or was it just not producing any sound?

Often if there is a fault with one speaker or the wiring to it the circuitry in the head unit will cut the signal the speakers to protect itself from a short circuit, so you get no sound. Some will do only one speaker, others may cut out everything.

 

You can unplug the head unit and use an ohmmeter to check resistance of each speaker circuit. Typical speaker resistance is about 4ohms, so it should be something close to that. If resistance is 0 the circuit is shorted or the speaker is shorted, if it is infinite the circuit is open (wiring cut or pinched or the speaker may be unplugged). Also check resistance between each speaker wire and chassis ground to determine short to ground. A short to ground will cause the head unit to go into protect mode.

Edited June 13, 201510 yr by Fairtax4me

To check the wiring and the speaker set the meter to read Resistance ®. Set the scale to a low number like 200 ohms since the speaker will only have around 4 to 10 ohms of resistance. Disconnect the speaker wires from the amp and place the meter probe leads across the speaker leads. If you have near zero ohms of resistance then there is a short across the wire. If the resistance shows real high or 'OL' then the there is a break in the wiring or the speaker coil is open.

Good Morning FairTax and Cougar - (FairTax you are pulling double duty!).  A disclaimer....I no nothing about electronics.  Here is the backstory. Impreza going on 14 years. Original Receiver replaced under warranty because it would get hot and CDs would skip.  Same with replacement.  Listened to radio for ten years. Then the receiver just died (or at least all speakers quit at once) - not just one speaker.  All I know to do is check fuses and fuses were always ok.  So I ordered a cheap Boss Audio with an aux port to play mps3's - that is what I am attempting to install.  I matched up the wires from the Boss Harnesses to the Scosche Harness (didn't solder, no butt connectors - just good twisted connections with black electrical tape until know everything will work) - plugged it in to the car's internal harness and everything works except left front speaker - which I assume means drivers side - yes?

 

When you guys are talking about testing resistance are you talking about putting the probes on harness that comes from inside the car?  

 

https://dl.dropboxusercontent.com/u/108322879/Car%20Harness.jpg

 

https://dl.dropboxusercontent.com/u/108322879/Car%20Harness%20CloseUp.jpg

 

Assuming I am checking "car" harness - should be car be switched on or running?

Thanks

When checking resistance you always want the power to be Off.

An ohmmeter puts a small electrical charge on the circuit you're testing. It measures how much it sends out and compares with how much of that current comes back through the circuit. Then using some fancy maths (based on Ohms law) it determines the resistance in that circuit.

 

Because it's applying current to the circuit, any power in the circuit will affect the reading, and can potentially destroy the meter.

 

Since the front left is the problem you're going to connect your meter leads to the wires for that speaker. That will check resistance of just the speaker and wires leading to it.

 

If you can unplug the harness from the head unit that will help because you can test that as well.

Did the Ohm test and the left front speaker does show 0L.  All other speakers show resistance and work.

 

So does that mean my speaker itself is bad?  Thoughts on what to do next?

 

Thanks everyone. 

Pull the door panel and check the speaker itself. If the speaker reads 4ish ohms and the connector is clean, check continuity of the wires from the speaker end to the radio harness end.