The factory IS300 E-shift buttons work like this: The buttons on the front of the wheel say DOWN. The buttons on the back of the wheel say UP.

I didn't like this configuration, so I decided to modify them so that they function in a similar way as to paddle shifters found on newer cars.

I decided to write this up, because when I google searched to see if anyone has done this before, no results popped up. Absolutely NONE on ClubLexus (ALL the groups) and nothing on my.IS.
*I can't confirm, but I think this modification should also work on GS300/400/430s.
**And I'm not 100% certainon this, but if a Lexus/Toyota OEM steering wheel can be mounted in the IS300 and the cruise control and e-shift buttons work perfectly fine, then this modification SHOULD work on those wheels too



Step one: Remove the airbag. Loosen the two TORX bolts. You will need a T27 bit. Once you have the airbag out, unplug the airbag harness. It's the yellow plug.
NOTE: It is important at this point that you do not turn on the car or put the key in the on position. If you do, the airbag warning light will turn on and stay on until you reset it.

Now you should be looking at the white plug. This has the horn wire, the cruise control, and the e-shift buttons on it. Unplug it, it gives you a bit more room to work with. I also slipped off the blue wire from the steering wheel bracket. After that I unwrapped some electrical tape from the wires going towards the left hand buttons.

Now here's the wires that are important on the white plug:

White & Black share the pin on the left.
Red & Blue share the pin 2nd to the left.

Wires to leave alone:
Yellow
Red with a black stripe
Blue wire (first pin from the right)

*You will see 2 wires that seem to go from one set of buttons to the other. Leave these alone as well:
White w/black stripe
Yellow


Stock:
The white wire goes to the left DOWN and the black wire goes to the right DOWN button.
The red wire goes to the left UP button and the blue wire goes to the right UP button

Give yourself some room to work with, at least 15mm of space on each side so you can strip the wires
- Cut the black wire from the first pin
- Cut the red wire from the 2nd pin

- Connect the black wire to the red wire coming from the left hand button
- Connect the red wire to the black wire coming from the right hand button

Here are some picts. I know they're big, but that's a good thing. Makes it easier to see what you need to do.
I took these picts AFTER I did the modification. So what you see here is a visual guide to what it should look like when you are done

This shows how the black and white wire are in pin 1 and the red and blue wire are on pin 2.
You will see that the black wire on pin 1 now connects to the red wire on the left, and the red wire on pin 2 connects to the black wire on the right









You are done!

Now both buttons on the left side downshift, and both buttons on the right side upshift. Just like paddles. Enjoy!



This is what it looks like finished

 

Oh, and to remind myself that I modified the buttons, I put a small square of black electrical tape covering the UP on the back of the steering wheel on the left side, and a rectangle of black tape covering the DOWN on the right facing side.

At some point in the future, I would like to have stickers made to cover the text, so that the DOWN is replaced with a (-) and the black rectangle has a (+)