For ‘16 and ‘17 LX570, the power lift tail gate is somewhat half functioned. You have the option to open it by remote, the push button on the dash, BUT, you just can not do the power open by punch the unlock button on the gate! What’s reason for Lexus to design that way is beyond my understanding. Starting ‘18 LX570, Lexus has added this function, now you will have the ability to just walk to the LX, push the rubber button on the tail gate, it will power open just as you push the button on the dash.

I always want ed to make this the same way on my 2016 LX570. After hours of researching, it appears the function is build into the Main Body ECU, which is impossible to replace as 2016/17 uses different ECU than 2018+ with different pin outs, which also impacts other accessory ECUs. So, in order to fix that, I will have to find another way. I looked both 2016 and 2018 LX electronic diagrams, all the switches and power lift gate control units are all the same. So, my logical think would be if I can using the signal from the tail gate push button, to trigger the switch on the dash, it will serve the same purpose to open the gate automatically.

Pin #3 on the tail gate push button is grounded when you press it for unlock/unlatch the tail gate. I initially tried to use it to control a relay then provide the contact for the switch on the dash (Pin #3 and #6) to power open the gate. That turned out it didn’t work. The reason is simple, it act as both buttons are pressed at same time, the LX just emitted a long beep. So to achieve that logical, I will need slightly delay between I push the unlock button on the gate and engage the push button on the dash. After a short search, I found this programmable timer is a perfect fit for my application:

Here is the diagram of the principle (sorry for my not so sophisticated engineering drawing):




Here are two parts and finished home made ECU:





The rest of things are just feed the wire from the gate, I am tapping into the fuse block for the inverter as it provides constant power. The timer only draw 0.3 mA as the stand by power.







I programmed timer with 1 second delay after receiving the trigger from tail gate switch, then engage dash open tail gate switch for 1 second since for open the tail gate from the dash switch require about 0.8 second of press. Here is the final results:

With LX unlocked, simply push the tail gate button, the tail gate opens automatically:


With LX locked, bush the button on the tail gate, the gate unlocks, then open automatically:


With that, now I have a fully functioned power tail gate, just as 2018+ LX. More importantly, I won’t hear anymore complains from someone at the end

 

This is awesome mod and love to do it on my 17. Too afraid to take the dash apart. So I’m clear, you need to run a wire between front dash fuse box all the way back to the trunk? If so that’s probably more than I’m comfortable DIY.

 

The principle is to get the trigger signal from unlock/open switch to trigger the open/close switch on the dash. So, one wire will need to run from tailgate to the front. Fuse box is for power for the timer and relay. You don’t need to remove the whole bottom part of the dash, it just needed to lose up a little to access the switch. It is held only by two 10 mm bolts and rest of plastic clips. Run the wire is more of time consuming job, there is many ways that you can hide wire, I just want to be perfect, and take the tailgate panel off and done it more OEM alike way. I have done it before when I replaced tail lights with sequential turn signals, so it is not too difficult. It is intimidating when you do it first time, but you will gain confidence quickly.

 

Impressive!!!! I am amazed by the amount of investigation you've put in.

 

I just hate the little imperfection, especially with Lexus

 

you did a great job, would you help me find out where to get the sequence turn signal rear tails for my 17” LX? And i am also live in ohio but in Columbus, thanks in advance

 

Turn relay for 16+ LX is build into the Body ECU, in order to change the turn signal for sequential, you will have to swap out all for pieces of turn signal units at rear. Since it did not meet US DOT regulation as current configuration, those units will need to be imported from Asia or European market. US spec turn signal units does not contain the LED nor the driver in the two inner pieces of the housing units. Other than that, you will need to add three wires should you obtained replacement turn signal units. Here is the detail I have posted on the forum:

https://www.clublexus.com/forums/lx-...installed.html

I am in sourthwest outside of Cleveland. If you happened travel up here, let me know and we can meet for a beer.

 

great, i am happen to be in Cleveland one in awhile to go to dum sum and park to shop market

 

@ohiois350 I have sent you a PM.

 

@ohiois350 your message box is full

 

sorry i just deleted some of my old messages