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-   -   No sound after changing radio? (https://www.chryslerforum.com/forum/chrysler-voyager-town-country-21/no-sound-after-changing-radio-5029/)

AlanC 04-03-2020 12:17 PM

I rewired my speakers with Andy's help. Full details are in this thread. https://www.chryslerforum.com/forum/...t-28640/page2/

Melanie_T 04-03-2020 12:22 PM

Yes but that again is a solution that doesn't keep the factory amp. What I found out is how to keep the factory amp. I'm going to extend it to provide 8 level speed dependent volume, then I'll do a writeup on our blog and will link to it. Also, my current software doesn't turn the amp off yet if the radio is turned off, it leaves it on until the car is turned off. So much work, so little time. If I had a list of the bus codes (not the OBDII ones!) that keep scrolling by whenever the car is running, that would be really great. I know I've seen such a list posted somewhere once, but I've lost the location.

AlanC 04-04-2020 04:48 AM


Originally Posted by Melanie_T (Post 114051)
Yes but that again is a solution that doesn't keep the factory amp. What I found out is how to keep the factory amp. I'm going to extend it to provide 8 level speed dependent volume, then I'll do a writeup on our blog and will link to it. Also, my current software doesn't turn the amp off yet if the radio is torned off, it leaves it on until the car is turned off. So much work, so little time. If I had a list of the bus codes (not the OBDII ones!) that keep scrolling by whenever the car is running, that would be really great. I know I've seen such a list posted somewhere once, but I've lost the location.

That's great for those that want to keep the factory amp but with a half decent head unit the factory amp isn't necessary, other than to keep the steering wheel controls.

Melanie_T 04-04-2020 05:40 AM

The factory amp has the crossover built into it. By wiring the speakers in series you get the 4 ohms you need for an aftermarket unit, but you're feeding full spectrum to speakers not suited for it. The amp splits the band to feed the proper frequencies to the speakers, that was my main reason for wanting to keep it at all cost.

shahbour 10-24-2021 08:41 AM


Originally Posted by Melanie_T (Post 114038)
Might be called a necobump, but I solved this.

You need to send these codes on the J1850 bus:

Amplifier on: 8D 0F 41
Volume 0: 3D 13 00 00
Pan/fade center: 3D 14 00 00
Bass/treble neutral: 3D 15 00 00
Amp set volume: 3D 13 18

They need to be re-sent (except for the volume 0 one!!!!!!) every about 850 ms.

You can NOT do this with an OBDII tester because it doesn't support one byte headers.

i need to ask about this
i have android player with canbus decoder
can i connecting the can+ and can- to J1850 ??
because my player car plug not have can+ and can -
what i can do ???

Melanie_T 10-24-2021 10:46 AM


Originally Posted by shahbour (Post 119908)
i need to ask about this
i have android player with canbus decoder
can i connecting the can+ and can- to J1850 ??
because my player car plug not have can+ and can -
what i can do ???

Sorry, you can't connect CAN and J1850. They are completely different, both electrical and protocol don't match.You would have to build a small circuit to send the radio turn-on codes, like I did.

shahbour 10-24-2021 01:54 PM


Originally Posted by Melanie_T (Post 119912)
Sorry, you can't connect CAN and J1850. They are completely different, both electrical and protocol don't match.You would have to build a small circuit to send the radio turn-on codes, like I did.

How i can do it?
And how i can connect the can bus decoder to can make wheel buttons on?

Melanie_T 10-24-2021 05:45 PM


Originally Posted by shahbour (Post 119914)
How i can do it?
And how i can connect the can bus decoder to can make wheel buttons on?

So, here's the complex bit.

You need to build a circuit that takes J1850 and matches it to microcontroller signals. I have such circuits and software for both ESP-32 and ATMega328 processors. The processor would also need to be connected to your CAN bus, that is possible only with ESP-32 as the Atmel processor has too little processing power. You would need to write software that receives your steering wheel commands from J1850 and sends out corresponding CAN messages to your radio. All this is not well documented. I have written software that uses an ATMega328 to control my amplifier and also convert chrysler steering wheel controls to Alpine remote signals (which themselves are not well documented). It requires quite a high level of knowledge about low level programming to do this. It can be done, but the learning curve is steep.

shahbour 10-25-2021 03:18 AM


Originally Posted by Melanie_T (Post 119917)
So, here's the complex bit.

You need to build a circuit that takes J1850 and matches it to microcontroller signals. I have such circuits and software for both ESP-32 and ATMega328 processors. The processor would also need to be connected to your CAN bus, that is possible only with ESP-32 as the Atmel processor has too little processing power. You would need to write software that receives your steering wheel commands from J1850 and sends out corresponding CAN messages to your radio. All this is not well documented. I have written software that uses an ATMega328 to control my amplifier and also convert chrysler steering wheel controls to Alpine remote signals (which themselves are not well documented). It requires quite a high level of knowledge about low level programming to do this. It can be done, but the learning curve is steep.

What i can to get all commans?

shahbour 10-26-2021 03:58 AM

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