Expert: Justin Wheeler - 1/9/2012

Question
I am troublshooting a Pioneer DEH P3100UB car stereo. The rear speakers of a 3 speaker system (1967 Dodge Charger) stopped working. After researching test methods using a volt meter, I understand I should get a movement on the 12v needle at the speaker connections as well as off the wire harness from the back of the head unit. The front speaker works but I do not get a reading when touching the leads to the pos and neg wires going to it. I accidently touched one lead to the radio case and got a reading. Testing the rear output leads I get no reading until I touch the casing with one lead again. Can you help me understand my problem here?

Answer
Hi Rick,

I'm not entirely sure I understand what you're saying about the testing.

What I can tell you is that testing the two leads on a speaker with a multimeter in DC mode won't get you any useful reading.

To test speaker wires, you need to test from the back of the deck itself to the speaker leads themselves with the system OFF using a voltmeter set to OHMs.  You should get less than 1ohm of resistance across each wire to the deck.

If they're good, then test the two speaker leads themselves without the deck connected.  They should read 4 ohms.  If not, the speakers themselves are bad.

(Although on a 1967 Charger, I may be wrong on the speaker impedance.  They should be labelled.)

Justin