QuestionI have a 1995 nissan Maxima, non-Bose system, aftermarket Pioneer deh2700 rec, single cd player, made all connections and the system powers up but no sound, any suggestions as to what may be the issue, I thought it might be a grounding issue but have eliminated that,It has good ground. I am completely stumped. I would be truly grateful for any advice.
Thank you so Much,
Tina
AnswerHi Tina,
When I see a problem like yours, it usually comes down to one of three things: a factory amplifier, a speaker wiring problem, or a defective head unit.
If you're right that the Maxima is not equipped with a Bose system, then you don't have a factory amp to worry about. That means you'll want to check for a problem with one of the speakers. Often there will be a speaker wire that's pinched or shorted to ground. A short on one wire will kill the sound to all the speakers, as the deck's built-in amplifier shuts down for protection.
First, check the connections behind the head unit for damaged or uninsulated wires. If a speaker wire has been pinched behind the head unit chassis when you push it into the dash cavity, that could be causing the problem. Another possibility is an exposed wire connection, if a crimp connector or electrical tape has come off.
If you don't see any problems behind the deck, you'll need to test the wires. Use a multimeter with a continuity function. Remove and unplug the head unit, then check each of the speaker wires for continuity with chassis ground. To do this, attach the black probe to a good ground point, and touch the red probe to each of the speaker wire terminals in the head unit plug. (The after-market speaker wire colors are white, gray, violet, and green; four of the wires will be solid color, and four others will have a black stripe). None of the wires should show continuity with chassis ground; if you have one that shows continuity, then it's the source of the problem.
If you don't find continuity to ground on any of the speaker wires, test the resistance of each speaker wire pair. Set the meter for DC resistance, and put one probe on the terminal for the white wire, and the other probe on the white/black wire terminal. You should get a resistance reading of 3 ohms or more. If you find a much lower reading, then you may have a speaker with a shorted voice coil. If so, you'd need to replace the speaker. Repeat this test with each of the speaker wire pairs.
If you do find continuity to chassis ground on any of the speaker wires, the most likely trouble spot is at the speaker itself. If you have after-market speakers, then it's possible one of the speaker wires has come loose from the speaker, and is touching the metal in the door. Sometimes you'll get a speaker with a defect where the speaker terminal is shorted against the speaker basket. In this case, screwing the speaker to the door metal will shut down the head unit's output.
If you don't have access to a digital multimeter, then you can try disconnecting all the speakers, and re-connecting them one at a time. If the head unit works with the first speaker, try connecting a second speaker, and so on until you find one that makes the head unit shut off. If it doesn't work with the first speaker, try a second speaker; if that doesn't work either, then it's likely that the head unit's internal amplifier is defective.
Hope this helps!
Brian
