Cheap A/c Control Panel Repair

thermoacc · April 7, 2009

Hi all....

Summer (I hope!) is on the way and I really diddnt want to look at the usual blank a/c panel on my Mk1, guessing the temperature setpoint or lowering the control and counting the number of beeps to set it to my preferred temperature. I have lived with this fault because I am not willing to pay the silly money for the usual repair or the stupid money for a new panel from Lexus. My car only being worth £600 on a good day, pushed me into taking out the control panel and having a poke about. The installed panel is unique in it`s application, but not in it`s dimensions...so a small 3.5 digit display was orderd from RS.

I took a couple of pics while I modified the unit to accept the display:-

Anyway, after a few hours, a bit of soldering and the use of some black insulation tape, I came up with this.....

It`s crude I know, but only cost me £5 odd and two hours, even the backlight works! The next step is to do the clock side of things using another lcd from RS. If it goes ok I`ll post the outcome.....if not, has anyone got a spare a/c control for a Mk1 LS400??!! Hahaha! :D

steve2006 · April 7, 2009

That's pretty neat for a fiver with free technical skills.

I did a few of the panels myself using the RHD US made replacements but like you say the cost of the LCD works out at around £60.00 plus fitting ( like you I am an electronics engineer so that cost nothing but time).

Let us see the clock replacement if you do it.

Mybikesacx500 · April 7, 2009

Hi all....

Summer (I hope!) is on the way and I really diddnt want to look at the usual blank a/c panel on my Mk1, guessing the temperature setpoint or lowering the control and counting the number of beeps to set it to my preferred temperature. I have lived with this fault because I am not willing to pay the silly money for the usual repair or the stupid money for a new panel from Lexus. My car only being worth £600 on a good day, pushed me into taking out the control panel and having a poke about. The installed panel is unique in it`s application, but not in it`s dimensions...so a small 3.5 digit display was orderd from RS.

I took a couple of pics while I modified the unit to accept the display:-

Now that's clever, it must have taken you a while to work out the pinouts, surely?

If you could sort out a clock, too, that would be a great service to us all

TeamDax · April 8, 2009

hahaha thats very clever..... i got an LCD from the US.... pretty much used all of my shonky soldering skills.... but it worked first time :)

i cant wait to see you get the clock working too

thermoacc · April 8, 2009

Now that's clever, it must have taken you a while to work out the pinouts, surely?
If you could sort out a clock, too, that would be a great service to us all

Hi,

The lcd`s have pdf info on the RS website showing the pin layouts so is easy to follow. The display addresses on the pcb are standard format with only a couple of them out of place. I`m gonna get another lcd soon and start the clock side which will hopefully be as straight forward as the temp display. With any luck and the use of sticky back plastic I should be able to repair the whole thing for a tenner!....more in my budget at the moment!

Redtwin · April 8, 2009

It looks like you have put the temp display where the clock display should be. Was that intentional?.

steve2006 · April 8, 2009

It looks like you have put the temp display where the clock display should be. Was that intentional?.

Your right never noticed that, I was amazed at the results, does this mean the climate control only comes on at certain times of the day now then? This also means sales to the USA with theirs being on that side. Quick get a patent on it.

thermoacc · April 8, 2009

It looks like you have put the temp display where the clock display should be. Was that intentional?.

Sort of ...it just made it easier to solder the hook-up wire for this experiment. Should have no problems moving the display to the correct location now I know it works. Just orderd another lcd for the clock after testing the output of the ic and should go according to plan. All I need is time now as the wife and kids dont like me spending time on myself! :D

Bladefire · April 15, 2009

Ive Just purchased an LS, last week, temperature control and radio works fine, as does the display. Only problem is, it doesnt light up, dont think it is the bulb(s), has anyone got experience of this and how to fix and where to get the bits from. Thanks ivan

thermoacc · April 15, 2009

Ive Just purchased an LS, last week, temperature control and radio works fine, as does the display. Only problem is, it doesnt light up, dont think it is the bulb(s), has anyone got experience of this and how to fix and where to get the bits from. Thanks ivan

Hi,

There are three led`s illuminating the display....these have probably failed on your unit. They are the twist in captive type and I have seen them on a few other cars-not only lexus. An a/c unit with a failed display from a scrapped car only fetches between £10 and £30, so you could take the led`s out of that. My route would be to get some from maplin and solder them in for pence!

TeamDax · April 15, 2009

Ive Just purchased an LS, last week, temperature control and radio works fine, as does the display. Only problem is, it doesnt light up, dont think it is the bulb(s), has anyone got experience of this and how to fix and where to get the bits from. Thanks ivan

Hi,

There are three led`s illuminating the display....these have probably failed on your unit. They are the twist in captive type and I have seen them on a few other cars-not only lexus. An a/c unit with a failed display from a scrapped car only fetches between £10 and £30, so you could take the led`s out of that. My route would be to get some from maplin and solder them in for pence!

i had one bulb out on mine, followed the instructions at http://www.lexls.com/tutorials/lighting/cl...cklighting.html

i was lucky enough to get replacement bulbs with the new climate control LCD which i was replacing at the same time