Question about 1998 Toyota 4Runner

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1998 Toyota 4Runner AMP + Radio doesn't work (externally)

So, I took out my Toyota Radio in my 4Runner and put in a NAV unit w/Bluetooth….(love it BTW). So I have the Toyota radio and the amp now and thought, rather than chuck this, why not make a garage radio and recycle this thing. I do stuff like this a lot and familiar with basic wiring. So I got the schematic, and located all the +- speaker leads, and the +- 12V leads, and then there are a few wires which their purpose isn’t noted, but are labeled in the schematic posted at: as “DO NOT USE.” I connect the unit up to 12V power source, the amp is getting power, and in turn passing it to the radio. I’ve grounded each chassis to the negative terminal, but the radio blinks on and off. I’m sure it’s code for, “You’ve got a short somewhere you idiot!” but I can’t find it. I’ve since checked the radio by plugging it back into the car and it works fine, without entering anti-theft codes. With my Porsche, if I unhook the radio from power, I have to re-enter the code to use it in the car. The Toyota radio, I unhook and re-plug it into the car, it’s fine. If I run the radio externally I get the blinking and no sound or function.

I did a little more research and the three leads that are labeled “DO NOT USE,” in the diagram, “J”, “N”, & “O” are as follows:
J is for Radio illumination
N is empty
O is for amp trigger (I assume this means it’s sending a voltage signal to turn it on/off) but I’m unclear on this

My guess is that I have to learn what the voltage signal the amp is looking for, because I’m pretty sure I have all the positive/neg leads correct, and I’ve grounded each related chassis to negative ground.
Thoughts? Is there something I'm missing?

Posted by on

  • dukfootball Feb 03, 2009

    bcbandit666, Thank you for the reply. I'm currently running 12 volts into the "switched" and "unswitched" leads. I'm assuming you're calling the "memory wire" as another term for the "unswitched" (always on)+ lead? On the diagram noted, "C & D" are switched and unswitched leads. "O" is the amp trigger. How would you recommend I wire the amp trigger? I don't know what information (voltage/amp) it needs.I'm concerned too, that "J' (Radio Illumination) may somehow be involved too. :-I

    Thanks again for your assistance!



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Sounds like you need the memory wire hooked up.

If the memory wire is Not used, you will get 1 of 3 things,
1 no Sound.
2 no Info, Like the Clock or Station
and 3 "IF the amp is wired Right" you would send the power Backwards to the radio.

Not to mention the voltage for the Amp Trigger is 12+ volts Just low Amps,

So you could wire Just the Radio With 1 ground, 2 hots And Ground the Radio Case, INcase the Radio is using the Ant as a Ground.

Hope this Helps.

Posted on Feb 03, 2009


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