Oldsports

I received an aftermarket radio/GPS unit as a present which I plan to install in my 2001 Lexus LS430 w/o navigation. I would like to connect it with my audio steering wheel controls - the new unit says it can decode the signals and has inputs for what it calls KEY1 and KEY2 which I assume should come from the steering wheel controls. However, looking at the Lexus wiring diagram I cannot find these signals; instead I find signals GTX+ and GTX- that connect the Gateway ECU to the factory radio.

In an older post someone said that the steering controls could be used for other purposes (i.e. telephone control) so the control wires probably connect into an ECU which can be programmed to provide the correct signals based on how the controls are being used. This seems to make sense based on how I read the wiring diagram.

Given all of this, I have a couple of questions:
1. Do the steering wheel controls connect to the Gateway ECU as suggested above?
2. If #1 is true, do the ECU signals GTX+ and GTX- match up with KEY1 and KEY2 of the new unit?
3. If #2 is not true, do I need to retrieve the native steering wheel controls (KEY1, KEY2) by splicing them from where they enter the ECU?
4. If #3 is true, is there another way to get to the native steering wheel controls other than splicing them at the ECU? Does someone make an adapter that takes the output of the ECU and converts it to the KEY1 and KEY2?
5. Finally, if #1 is not true (the steering wheel controls DO NOT connect to the Gateway ECU), can you tell me where they are? I cannot find them anywhere on the wiring diagram that I have.

Thanks in advance for your help!

tradosauru

I'm having Best Buy install a new Sony WXGT90BT that is satellite ready tomorrow. The installer said that he might be able to hard wire the steering controls to the receiver or possibly have an installation part.
If so I will report back on my findings. He also said he should be able to hook the satellite radio with a special part.

iToaster

The steering wheel controls on the LS aren't like the ones on most vehicles. Most vehicles use a resistor based setup with switches that feeds directly into the head unit, so hooking them up to a new radio is fairly simple. The LS, on the other hand, has a computer in the switch that detects which button is pressed and sends the information digitally to the gateway ECU, which then gives the AVC LAN system a command. I've seen people in the GS community hack apart their steering wheel controls and solder resistors to the switches, then bypass the steering wheel control computer, but it's a little messy.

Oldsports

Does anyone know if the LS430's steering wheel control inputs to the radio are the same as the GS430 and/or SC430? I found two steering wheel control adapter interfaces (ASWC-TOY-LEX and ASWC-1) that work with the GS430 and SC430. I contacted the manufacturer (Axxess); someone from their tech department says that the units have not be tested with the LS430 so he could not say if they would work with the LS430.

tradosauru

The Best Buy technician said he could most likely get the steering wheel controls to work but not after a lot of extra wiring. The ASWC-1 was not going to work.

Oldsports

Yes - a little more research showed me that the ASWC-1 would not work. I am still holding out hope for the ASWC-TOY-LEX since I am sure it works with the GS and SC models. Can the LS be that much different? It is a $40 gamble to try it.

tradosauru

Save your receipt so you can return it if needed.

I usually buy mine from Amazon.

Oldsports

tradosauru,

Did the Best Buy technician get your controls to work? If so, can you share what the technician did? It appears that there are no adapters on the market that work with the LS430 controls so I may have to do what he did if I want my buttons to work. Thanks!

tradosauru

I told the technician not to bother with it as it would incur more charges. He indicated that the controls could be integrated with the new receiver.


I'm surprised at the lack of aftermarket parts such as all weather mats for the LS430.

Oldsports

tradosauru,

Thanks for your replies. I am also surprised at the lack of aftermarket products for the LS430.

It looks like if I want the controls to work, I will need to hack into the controls as iToaster said the GS community has done. I found one post on the process - it was cleverly done. The only concern is that you do have to cut and splice a couple of wires which would have to be repaired if I ever wanted to go back to OEM. I don't know how different the LS controller is from the GS so I may not be able to follow the instructions exactly but I guess I can figure it out. If you have seen a hack for the LS430 posted somewhere, let me know.

Thanks!

Oldsports

This is the post that details how the person in the GS community got his steering wheel controls to work:

https://www.clublexus.com/forums/gs-...-headunit.html

I have not yet opened up the LS430 controls but I assume that they are switches that open and close like the GS so I should be able to replicate the resistor network. What I don't know is which clockspring wire is not used so I can feed the signal from the resistor network through the clockspring and to my audio head unit. For the GS hack, he used the telephone wire. Does anyone have a clockspring wiring diagram so I can determine which connection I can use for my version of the retrofit?

Thanks!

Oldsports

I just finished installing my aftermarket radio. It works well but I miss my steering wheel controls!! I thought about hacking into them like I saw on the GS Forum but I decided against it. However, iToaster's explanation about how the controls interface with the ECU got me thinking about a different way to go.

I am somewhat competent in building electrical circuits so I would like to try building my own SWC interface since none is commercially available. I know that the steering wheel controls are communicating with the ECU and there are two wires (GTX+ and GTX-) that are delivering the signals from the ECU to the radio unit. If I can decode the GTX+ and GTX- signals I can build a circuit to interface with a resistor network that would provide the proper signals to my aftermarket radio's steering wheel controls.

Does anyone know where I could get more information about the steering wheel control signals? A quick search of the Internet did not yield anything. Does anyone know of a technical connection to Toyota/Lexus I could try? They may not want me hacking around their controls but it is worth a shot.

Thanks!

iToaster

In theory, it could work. The problem is that most of the communication network in the vehicle is a proprietary system with little data available on the fine details. You could take the components apart and look at the part numbers on the chips, but my guess is that they're ASICs and don't have any published information.

vadorade

Hi Oldsports,

Did you ever figure out a way to connect the steering wheel controls? I am installing a stereo and am too accustomed to using my wheel controls...would like to keep them if possible. I found this video on YouTube of a guy using his controls, so there is some proof that it is possible.

https://youtu.be/8evnXLAQrEM


btw, thanks for your how to posts..it has helped immensely with my install.

Oldsports

Hi vadorade,

Unfortunately I did not figure out how to get the steering wheel controls to work. I saw the video and it appears that someone has figured it out. It might be worth it to try to contact the video maker to see if he will respond. If you find out something, let me know. I want my steering wheel controls back!

Thanks!