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Discussion Starter #1
I tried researching and couldn't find anything.
So I installed this headunit a couple weeks ago, and out of nowhere, it stopped putting out sound, but the deck/screen worked perfectly. So I put the stock stereo back in, and the sound works fine.
I return the Jensen for a brand new one, install it, and again, no sound at all.

Pretty certain I have a base stereo. It's a 94 Miata. Has the two harnesses. One harness for the headrest speakers, and the other for power/switch/door speakers.

This is the wiring diagram I used:
http://www.madracki.com/miata/images/wiring/94sys.pdf

TIA for any and all help.
 

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Get a multimeter set it to AC, turn on the radio and tap the positive and negative of each speaker channel on the head unit harness. If you're getting voltage it's your wiring if not it's a problem with the unit. If you have a spare speaker laying around you can just try each channel with that too instead of the multimeter. Also in the future please use a wiring harness, it's $4 with shipping, much easier and keeps you from hacking up the stock harness.

Most head unit amps will also go into protect mode turning off the internal amplifier if there's a short on one of the channels.
 

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Get a multimeter set it to AC, turn on the radio and tap the positive and negative of each speaker channel on the head unit harness. If you're getting voltage it's your wiring if not it's a problem with the unit. If you have a spare speaker laying around you can just try each channel with that too instead of the multimeter. Also in the future please use a wiring harness, it's $4 with shipping, much easier and keeps you from hacking up the stock harness.

Most head unit amps will also go into protect mode turning off the internal amplifier if there's a short on one of the channels.
What he said. I'd suggest measuring the resistance (well, technically impedance, but that's not important now...) of each speaker FROM THE HARNESS AT THE RADIO. Each speaker (+ side to - side) should be ~ 4 ohms (not sure about the headrest speakers, but probably the same). If its <1ohm, your speaker is shorted. If it's >8ohms, it's probably blown, but that's not likely if you've got sound off your factory HU.

Also, measure resistance of each speaker connection to ground (the metal frame under your dash is a good spot to get a chassis ground). If any of your speakers reads anything other than OL, it's shorting to ground, which is bad news. Means you need to fix your speaker mounting or wiring harness, but you have to find the problem first. PITA.

Hope this helps.
 

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Discussion Starter #4
Thanks for all the input. I tested constant, ignition, and ground. All were giving good power. I was getting zero power the all of the speakers so I just returned it and used the money for spacers. :p
 
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