# Aftermarket Stereo won't turn on/off with ignition key!!!!



## SoggySteve06 (Jul 12, 2012)

I know this question has been asked several times before but when i was reading the forums I still havent gotten an answer. I am no car audio expert by any means so if someone could shed some light on my problem that would be wonderful.

I have a 2003 Jetta with the double DIN monsoon stereo. i replaced the stereo with a kenwood and matched all the wires (by color, and instructions) betweeen the two wire harnesses that i bought offline. The stereo and all the speakers work but i have to manually turn on and off the stereo when i get in and out of the car. I dont know if the harnesses have the wires mixed up or if theres somthing special i should do. 

I have gone back to the harness and switched the Batt. Constant wire and the switch wire ( Red and yellow) so that red and yelllow were connected. when i did this nthing changed. i still had to manually turn on and off the stereo.

If anyone has any ideas i could try or know what im doing wrong Please HELP! If you need more Info just ask and ill let you know. THANK YOU!


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## 00jettavr6_2.8 (Jan 4, 2012)

your remote wire either isnt connected or connected to the wrong wire. there should be a royal blue wire from the head unit to the new wiring harness that should be connected. this wire is responsible for power the unit when the car is started and turned off


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## pcm1978 (Apr 16, 2003)

Did you use a voltmeter to check which lines you were using? Connect black lead to ground wire (usually brown) or bare metal somewhere on the body, and use the red to probe the leads. 

Whichever is constant 12V+ on your head-unit (yellow on mine, I think - it's often the fatter wire) needs to be hooked up to something that is always on. The switched 12V+ needs to be connected to something that is on only when the key is on.

Also, not sure about MkIVs but in my MkIII the head-unit switched power does not shut off until you pull the key out of the ignition. If you put the key in it stays off until you turn the key to the on position, but once the key is in the on position, you have to switch it off and then pull the key out in order for it to shut off.

If you need to tap into switched power for this, check the lines going into the rear defog switch - I think that is what the pros did in my MkI.


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## SoggySteve06 (Jul 12, 2012)

00jettavr6_2.8 said:


> your remote wire either isnt connected or connected to the wrong wire. there should be a royal blue wire from the head unit to the new wiring harness that should be connected. this wire is responsible for power the unit when the car is started and turned off


i have the royal blue wire from the head unit but there is no blue wire coming from the other harness. there is a blue and white wire that says AMP Turn on, but that is the only blue wire coming from the cars harness. and I have 3 blue wires on the head unit side, Solid blue, Blue and White(Amp turn on, goes to my sub) and a blue and yellow wire. the Solid blue and blue yellow wire i have going to nothing cuz there is no corisponding color


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## 00jettavr6_2.8 (Jan 4, 2012)

SoggySteve06 said:


> i have the royal blue wire from the head unit but there is no blue wire coming from the other harness. there is a blue and white wire that says AMP Turn on, but that is the only blue wire coming from the cars harness. and I have 3 blue wires on the head unit side, Solid blue, Blue and White(Amp turn on, goes to my sub) and a blue and yellow wire. the Solid blue and blue yellow wire i have going to nothing cuz there is no corisponding color


do you have an amp in your car? sorry should have asked that first. i have the blue wire from the head unit attatchedto my remote wire running from my amp


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## SoggySteve06 (Jul 12, 2012)

00jettavr6_2.8 said:


> do you have an amp in your car? sorry should have asked that first. i have the blue wire from the head unit attatchedto my remote wire running from my amp


I do have an Amp. its on my sub and the blue and white wire from the head unit is what turns it on. i have another blue and white wire coming from the car harness but that does nothing. then the solid blue wire has no writing on it and same with the blue and yellow. IDK what they do or what wires to attatch them to.


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## Rockerchick (May 10, 2005)

So I take it you removed the Monsoon amp? Or at least don't have it hooked up?


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## SoggySteve06 (Jul 12, 2012)

I figured it out. I had to run the red switch wire into the glovebox and got power from the glovebox light. when you remove the light the wires will only give power when the car is on Even if the glovebox is closed. Thanks for the Help!


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## Josiechapman (Jul 20, 2021)

I have a question about my 2007 VW Jetta, I installed a new aftermarket radio and the problem I am having is the radio turning off after the key is removed. I tested the red and yellow wire with the switch off and both have constant 12 volts. How do you get the acc wire to turn off when you turn the switch off?


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## alphastep11 (Feb 23, 2016)

Sorry to revive this, but I got a head scratcher. So when I plug in the access module to my car without the radio, I have 14 volts across the switch power and ground. Then I do the initialization. After that, I have zero volts across the switch power and ground with the key on and off. Even with the car on.
My radio does not turn on at any point in time ever (factory radio is good though).
Any ideas here?
I've checked for continuity the yellow battery wire, the red switch wire, and the ground wire. I have continuity across all three individually and I have voltage at the yellow and ground, and the red voltage is as told above.


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