Climate controls not working most of the time

[AntC]

Hello everyone,

 

I've been reading the forums for a while now regarding all kinds of topics concerning the IS 250, but I seem to have an issue that I have yet to find a solution to.

 

I have an '06 IS250 with the navigation unit. I'm not from the UK, but I bought the car from there last summer.

 

The issue I'm facing is that some of the climate control buttons are not working most of the time, I am referring to the ones seen here:

 

https://prnt.sc/10iy5hr

 

This is a pic I found on the net because I'm not near the car at the moment, however, the navigation unit is exactly the same as this one.

 

The highlighted buttons are the ones that I'm having issues with. To elaborate further, the green indicator light and the buttons themselves do not light up when I turn on the lights at night. The Auto button and Rear heaters button will sometimes work, as long as the car is in working temperature.

 

The Off and Front defog button will work very rarely, and the Circulation and Cabin vent buttons have never worked.

 

I once had all the buttons light up at night, though this wasn't under any specific circumstance, they just simply lit up, though the Circulation and Cabin vent buttons did not work at all.

 

Even when working, the green indicator or backlight do not light up.

 

As far as I am aware, the previous owner had someone change the navigation touch screen because of issues and I guess that something may have been damaged during the assembly/disassembly.

 

I'm ruling out a fuse as the issue, because if that was the case, the buttons would not be working at all (and I assume the entire navigation panel).

 

I've researched a lot regarding this issue, though I have yet to find any information on this specifically, the issues I've read about were mostly all buttons not working, or the entire unit. Now, the AC works without any issues when controlled with the touch screen, but I obviously can't use all functions without the physical buttons and can turn the ventilation off only using the Voice command.

 

Up until now I've just tested some basics such as removing the Battery for half an hour, pressing the buttons under different angles, restarting the nav unit.

 

I previously posted on a different forum and one member suggested that this can possibly be repaired, but would require taking out the navigation unit and taking pictures so that he can confirm.

 

At this point, I'm rather reserved on taking out the entire unit for fear of damaging it and the dashboard. (The previous touchscreen repair has damaged the dashboard a bit, unfortunately).  I've also checked on purchasing a new or second-hand unit, but the cost is quite high and would like to avoid it if possible.

 

I'll be heading to a Toyota/Lexus dealership next week for a firmware update and some basic diagnostics and will make sure to ask them about this, though I would assume that they will suggest replacing the entire unit.

 

I will greatly appreciate any provided information and suggestions on how to troubleshoot the issue without taking out the unit if possible.

 

Cheers

[Mr Vlad]

I'd suspect that whoever swapped that radio unit and slightly damaged the dash also either forgot to plug a plug in (there are a few behind the unit) or the replacement unit had/has a fault within it. Let us know what your Lexus dealer says. 

[AntC]

Thank you for the suggestion Mr. Vlad.

 

This also crossed my mind, but wouldn't an unplugged cable prevent the buttons from working entirely? 

 

Also, just to clarify, only the touchscreen was replaced, but the entire unit was taken out to do so.

 

I will keep you posted in case anyone faces the same issue.

 

Thanks

[Linas.P]

1 hour ago, Mr Vlad said:

I'd suspect that whoever swapped that radio unit and slightly damaged the dash also either forgot to plug a plug in (there are a few behind the unit) or the replacement unit had/has a fault within it. Let us know what your Lexus dealer says. 

If they changed the screen, then whole unit does not need to be changed. It is easy to assume they damaged something internally when replacing the screen or didn't connect the buttons properly.

Sadly, there are no information of how to fix the head-unit itself or wiring diagrams as far as I know... so the only option is to replace the unit. The instructions only shows how to remove the unit from the dash.

I personally wouldn't worry to much as I have very low regard for built in sat-nav on mk2 is (I consider it useless), so I would simply upgrade it with android unit which comes with all new keys anyways.

If you really want to keep original unit, then the only option would be taking it out and taking it to someone who specialises in electrical repairs. 

[AntC]

Hey guys.

I had nothing to do today, so I decided to grab a friend and to see if we can fix this.

To my surprise, the issue was caused by an open bracket of the flat cable that connects these buttons to the nav unit.

Basically, the cable was plugged in, but the open bracket meant that it can wobble around, which is why the buttons would only work occasionally.

I guess that they forgot to plug it in after the touchscreen change.

I also made some photos in case someone else decides to take their unit apart. Turns out, it wasn't that difficult of a process.

I skipped photos of taking out the nav unit itself, because there are plenty of YouTube videos that can be used for reference, which is also what we did.

So, when you've taken out the unit, you need to remove the climate control plastic panel. The first photo shows the bolts that you need to take out. They are the same on both sides:

The white connector you can see in the second photo was placed on the highlighted metal piece. On the inside, there is a plastic bracket, but to remove it, you need to bend the metal piece a bit and then bend it back in place during assembly. You need to remove the cable from this to be able to open the front panel:

 

From there in, you just need to gently pry the panel at the top, and below, at the gap between the radio and climate controls. I didn't take a pic of this, so just found one from the net for reference:

Third photo, you can see the flat cable that leads to the climate control buttons. You can see the empty holes where I removed the bolts to reach the buttons, but that wasn't necessary:

Final photo, you can see the silver bracket for the flat cable connector. This is the bracket that was left open and caused the mentioned issues:

All climate buttons are now working without any issues.

Thanks again for your information, hope someone finds this useful.

Cheers

 

Edited from PC to make the post easier to read.

 

One more edit: Just a heads up, there is also a cable connected to the front panel that you need to remove to be able to fully take it out, so take care not to pull on the panel too hard.

 

 

 

[Mr Vlad]

Well done Anton and your friend 👏