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Help with stereo wiring and amp

Baddy McBadface

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Hi all. Hoping someone can help this idiot out with the stereo and amp in my tj. Here's what I'm dealing with. The prior owner installed an amplifier and aftermarket sony head unit (my guess is 10years old). I noticed that the red hot wire to amp was not hooked up. It was just loose under the seat (maybe it was taped at some point and the tape unraveled) and I never noticed it wasn't connected. Anyway, seeing this I decided to place the wire onto the correct terminal of the amplifier. Doing this then caused the head unit to turn on and off repeatedly even though the keys were not in the ignition. The amp is grounded to the tub and there is the blue wire also going to the amp. I have not been able to figure out what is wrong. My guess is something isn't correct in the head unit/wire harness area but I can't make heads or tails of what is what. The amp seems to be wired correctly with a line directly from battery with an inline fuse. Amp is supposed to be for two speakers in the rear. That all seems to be wired correctly too since i can get sound from them when i have the red line connected to the amp. I don't want to leave it connected since it would drain my battery with the constant powering on and off of the head unit. Appreciate any advice and thank you.

jeep wires.jpg
 

Mitchrb1

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I'd download schematics for your Sony radio and double check every wire. But, the blue wire on the amp itself is normally the one that gets run to the back of the radio to a power on wire? like a power antenna or a wire specifically for a subwoofer or amp. That way it only comes on with the radio being powered on. At least that's the way my kicker subwoofer with built in amp works.
 

macleanflood

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Make sure the wire running to your amp is fused at the battery. I prefer running those wires in protective wire looms...split loom or better braided loom.

Many a vehicle fire was caused by folks not properly fusing things.

Second issue to pay attention to is grounds.

You might need to up the gauge of your chassis grounds if the amp is chassis grounded.

And don't assume the PO did anything right or used the proper gauge of wire...check if it's coppernor aluminum...had a friend chase stereo issues for years until he figured out the shop that installed it used aluminum (which needs sized bigger).

Good luck keeping the smoke inside!

-Mac
 
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Mitchrb1

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1669069528845.png

you didn't list radio model but here is one i found for Sony. You might have the blue wire hooked up to that Yellow wire supplying power all the time instead of the blue/white amp turn on wire.
 
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Necro

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Jun 22, 2022
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Norfolk Virginia
looking at the pic provided the amp turn on has been spliced into the acessory wire. That radio doesnt seem to have an amp turn on lead. The amp is backfeeding a little voltage back up the turn on wire and is powering up the radio briefly. Maybe install a diode on the amp turn on wire so it cant backfeed. Or get a amp turn on module that can be wired up behind the radio that will provide an amplifier turn on signal when it senses the radio turn on. Ultimately it seems something is wrong with the amp though because it shouldnt feed back up the turn on wire in the first place.
 
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Baddy McBadface

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Nov 21, 2022
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Pennsylvania
View attachment 378505
you didn't list radio model but here is one i found for Sony. You might have the blue wire hooked up to that Yellow wire supplying power all the time instead of the blue/white amp turn on wire.

Thank you. It is a Sony mex bt3800u.
View attachment 378505
you didn't list radio model but here is one i found for Sony. You might have the blue wire hooked up to that Yellow wire supplying power all the time instead of the blue/white amp turn on wire.

Thank you. It is a Sony mex bt3800u. I don’t see a blue white wire in that mess to connect the blue amp wire to. Could it be this unit was never compatible with the amp?
Ps: thank you everyone for the replies and assistance. This is my first time posting and I really wasn’t expecting any responses. Appreciate you all.
 

Necro

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Jun 22, 2022
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Norfolk Virginia
Hi all. Hoping someone can help this idiot out with the stereo and amp in my tj. Here's what I'm dealing with. The prior owner installed an amplifier and aftermarket sony head unit (my guess is 10years old). I noticed that the red hot wire to amp was not hooked up. It was just loose under the seat (maybe it was taped at some point and the tape unraveled) and I never noticed it wasn't connected. Anyway, seeing this I decided to place the wire onto the correct terminal of the amplifier. Doing this then caused the head unit to turn on and off repeatedly even though the keys were not in the ignition. The amp is grounded to the tub and there is the blue wire also going to the amp. I have not been able to figure out what is wrong. My guess is something isn't correct in the head unit/wire harness area but I can't make heads or tails of what is what. The amp seems to be wired correctly with a line directly from battery with an inline fuse. Amp is supposed to be for two speakers in the rear. That all seems to be wired correctly too since i can get sound from them when i have the red line connected to the amp. I don't want to leave it connected since it would drain my battery with the constant powering on and off of the head unit. Appreciate any advice and thank you.

View attachment 378476

There is an extra Yellow wire also. Traditionally the yellow wire is constantly hot for the radio and the red wire is the switched ignition. Hard to tell in this pic if the yellow wire is also spliced into the red and blue wires through the butt connector?
 
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Baddy McBadface

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There is an extra Yellow wire also. Traditionally the yellow wire is constantly hot for the radio and the red wire is the switched ignition. Hard to tell in this pic if the yellow wire is also spliced into the red and blue wires through the butt connector?

Both the blue amp wire and the yellow are connected to that red via that blue connector. Does this mean it is wired incorrectly or that the stereo (sony mex bt3800u) was never compatible with the kicker amp?
 

Necro

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Norfolk Virginia
Both the blue amp wire and the yellow are connected to that red via that blue connector. Does this mean it is wired incorrectly or that the stereo (sony mex bt3800u) was never compatible with the kicker amp?

Not necessarily. Depends on where the other end of the yellow wire is connected? It doesn't appear that that head unit has an amp turn on wire, which is weird for a newer radio. I do know that some installers de-pin the wires not used in the initial install to prevent shorts, but I've never heard of anyone de-pinning the amp turn on wire. There's a company names Schoche that makes an amplifier turn on module that used to cost 9.99 and it wires into the factory power wires and one of the speaker wires. When it senses music playing on the speaker wires it turns on the amplifier. If I had a radio with no amp turn on wire, I would install the Schoche piece. The benefit is that the way the amp is wired now, if you turn on your Jeep the amp will come on, even if the radio is turned off. Sometimes that can cause a feedback or a hum etc.. Having the module will turn off the amp when the radio is shut off instead of only when the Jeep is shut off.
 

Necro

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I'd multimeter the white wire with the blue butt connector. That might be the amp turn on. The other 2 white wires are the front speaker. Ground the black probe of a multimeter, put the meter on dc voltage, then measure the white wire with the blue butt connector and turn the radio on and off. If the wire comes on with the radio on and goes off with the radio turned off then you've found the correct wire. Also I noticed a din cable is plugged into the back of that radio. Din cables used to go to CD changers but nobody uses those anymore. What is the din cable for?
 
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Baddy McBadface

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I'd multimeter the white wire with the blue butt connector. That might be the amp turn on. The other 2 white wires are the front speaker. Ground the black probe of a multimeter, put the meter on dc voltage, then measure the white wire with the blue butt connector and turn the radio on and off. If the wire comes on with the radio on and goes off with the radio turned off then you've found the correct wire. Also I noticed a din cable is plugged into the back of that radio. Din cables used to go to CD changers but nobody uses those anymore. What is the din cable for?

OK. So here's what i was able to figure out with the multi meter. The white with the blue butt connector gets nothing. If the DIN cable is the big black one on the left that i believe is for a sirus satellite receiver.
I tested the cluster of red/blue/yellow wires that are all connected with the blue connector. They get 12v when the car is on as well as accessory on. When the car is off no keys they still get 2ish volts.
The blue remote with to the amp gets 12 v when the key is on and 2is v when there is no key.
When I hook the red wire back to the amp i get 12 v on that and 12 v on the blue remote wire with no key in ignition. But this is what causes the stereo to beep and click on and off. Also noticed there is a clicking sound that originates in the key area. Like it is activating the accessory wire.
Still lost on how to correct. I'm thinking that the issues have to do with the blue remote wire and the other yellow wire hooked up to the red accessory wire.
 
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Baddy McBadface

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Not necessarily. Depends on where the other end of the yellow wire is connected? It doesn't appear that that head unit has an amp turn on wire, which is weird for a newer radio. I do know that some installers de-pin the wires not used in the initial install to prevent shorts, but I've never heard of anyone de-pinning the amp turn on wire. There's a company names Schoche that makes an amplifier turn on module that used to cost 9.99 and it wires into the factory power wires and one of the speaker wires. When it senses music playing on the speaker wires it turns on the amplifier. If I had a radio with no amp turn on wire, I would install the Schoche piece. The benefit is that the way the amp is wired now, if you turn on your Jeep the amp will come on, even if the radio is turned off. Sometimes that can cause a feedback or a hum etc.. Having the module will turn off the amp when the radio is shut off instead of only when the Jeep is shut off.

I agree, it doesn't seem like there is a amp remote turn on wire in this unit. The unit is from 2010 if my research is correct. Not sure what the other yellow wire is.
 

Necro

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OK. So here's what i was able to figure out with the multi meter. The white with the blue butt connector gets nothing. If the DIN cable is the big black one on the left that i believe is for a sirus satellite receiver.
I tested the cluster of red/blue/yellow wires that are all connected with the blue connector. They get 12v when the car is on as well as accessory on. When the car is off no keys they still get 2ish volts.
The blue remote with to the amp gets 12 v when the key is on and 2is v when there is no key.
When I hook the red wire back to the amp i get 12 v on that and 12 v on the blue remote wire with no key in ignition. But this is what causes the stereo to beep and click on and off. Also noticed there is a clicking sound that originates in the key area. Like it is activating the accessory wire.
Still lost on how to correct. I'm thinking that the issues have to do with the blue remote wire and the other yellow wire hooked up to the red accessory wire.

if the din cable is going to an external module those extra wires might be the power wires to the module. If the white wire isn't getting power then it's not the remote and I'm not sure what it would be going to. Maybe put the amplifier turn on wire onto a relay that cuts the ckt when the key is turned off to prevent it from trying to backfeed the radio.
 
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Baddy McBadface

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if the din cable is going to an external module those extra wires might be the power wires to the module. If the white wire isn't getting power then it's not the remote and I'm not sure what it would be going to. Maybe put the amplifier turn on wire onto a relay that cuts the ckt when the key is turned off to prevent it from trying to backfeed the radio.

Didn't even think about the yellow being for the sirus receiver. At this point i'm starting to wonder if it wouldn't be easier to get a new stereo and start from scratch. Your suggestion about the relay....what does that mean?
 
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Necro

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Didn't even think about the yellow being for the sirus receiver. At this point i'm starting to wonder if it wouldn't be easier to get a new stereo and start from scratch. Your suggestion about the relay....what does that mean?

A 12 volt bosch square relay. Wire it so when power is cut off to it is disconnects the amp turn on wire.
30 to the amp, 87 to the yellow wire, 85 to ground, and 86 to the red wire. It should cut off when the key is shut off. If it doesnt move the wire on 87 to 87a. I forget off the top of my head which way it switches but its one of those 2.
 
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Baddy McBadface

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So I took the dash apart further. The yellow wire does go to a sirus receiver mounted under the steering wheel. The way it is currently wired with the amp should technically work as all is powered by the red accessory wire. The red accessory wire had 2 volts even when no key, 12volts with key. Is it supposed to have current all the time?
Is there a different wire I could tie the blue amp remote wire into ? Could the problem be the amp itself sending current back through the remote wire? I feel like when the amp is hooked up and voltage goes back through the remote wire it is somehow activating the red accessory wire as well as the stereo. That might explain the clicking I hear in the key area. It also supplies constant power to the stereo allowing it to operate sans keys