Service manual: http://www.manualslib.com/manual/902...8517zt-Uc.html
Album: http://imgur.com/a/yY9IS

Alright so I did a ton of digging and I didn't find a sliver of information on anyone simply putting an aux cord into their 2002+ ES300 without nav. I think I have it figured out, but feel free to add/correct anything. I am not in any way an electrical engineer.

I searched the service manual in hopes of finding any way to install an aux jack.

You'll need a soldering iron, the tools to remove the radio, some heatshrink/electrical tape, and a 3.5mm audio cable.





So here's our money maker. The pinout for the radio shows us where a line-level output is. I figured we can just piggyback off that and splice in our own aux cord!



Here's the connector itself. What we're dealing with is

Green: L+
Red: L-
Black: R+
White: R-



My donor aux cord, stripped and ready.



Here are the wires separated on the harness, green/red and black/white.





What I did is just installed the aux cord in parallel. Someone's probably gonna tell me this isn't good but it works.



Just put it to CD and play the CD upside down so you get an error and it's silent. Then just crank the volume on your phone and listen to some jams!

 

Why would you hook a line level INPUT into the line level OUTPUT on the radio? Maybe you misspoke.

 

Yeah I didn't write this very well (or design the circuit well lol). It's more of a proof of concept than an actual guide. I wrote it in hopes someone could improve it, just because I don't know much but I haven't found ANY info on anyone doing this. This works method works just fine by the way.

It's quite a ghettorigging, so yeah it's kinda set up like that. I didn't get around to designing a circuit that can switch between the inputs heading to the amp.




Ideally you'd set up a switch that can switch between the aux cable feeding the amp, or the radio feeding the amp. You can keep the positives running in parallel, but then just grab a SPDT switch to toggle between the respective ground connections.

Edit: instead of a switch can you just add some diodes? this is what I mean by I'm not expert.

 

If it works then the L+ and L- and R+ and R-are line INPUT pins, not line OUTPUT pins. Which brings up another question - WHAT would be coming in on those wires? Unless the wires go nowhere on the other end!! Maybe it's the CD input.


Maybe someone with more knowledge can chime in here.

 

I should mention that I tested if the whole thing would even work by splicing into one of the wires heading away from the radio, while leaving the the channel output on the radio disconnected. It's definitely an amp on the other end.

 

I've done the AUX hack to my Solara and my brother's Lexus GS300. In those cases we used the cassette player's L & R ports to solder to.


However the cassette deck in my brother's GS300 started giving trouble and he decided to do what you did, which is to solder in line level input lines from the CD deck going into the radio and play a CD to fool the radio into taking audio from that source.

He was also able to rig up a flip switch to flip between actual CD input and aux input. As a bonus he even added a cheap bluetooth adapter so now he's got bluetooth on his 16 year old car for <$10

 

Man, thank you SOOO MUCH! I hope you will read it.
i just have bought Lexus ES300 2003, in Ukraine, also, our situation in country is extra bad and i have no money for buying aux kit that connecting to cd changer connector.
so i have readed your post and have tried to do everything exactly like you. Also, i have watch in youtube how to disassembly all central console inside of car.

so, once again, thank you very much for your post. I have saved my money, also i mist work all day long, 12 hours, for getting this money but i have maked aux by your way for free

 

Also, music will play if you will choose the radio, so if you want to listen the radio - you must turn of music on your phone or music player that connected throught aux cable.
and, also, thank you for link to gallery, because only in gallery - quality of picture is so good that i can see L+ L- signs, e t c.
link for manual is in bad quality and text is non-readable on it.