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Webby123

Faulty Climate control / air conditioning

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I have recently purchased a used 2008 RX400h but unfortunately the air con is not working correctly. The left hand vent will blow out hot and cold air but the right hand one only hot air, not ideal as summer approaches. I have taken it today to a reputable car electrical workshop and unfortunately his fault find machine could not connect/sync to the car so could not see if were any fault codes. I would take to Lexus but I live on Isle of Wight and the nearest dealer is Southampton. They are quoting min two hours to run diagnostics at £130 per hour and then want the car for two days to try to establish the problem which will be an uneconomical repair for a car that cost £8000.  Any suggestions as to what the problem could be and how to resolve would be greatly appreciated.

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Hi. On most RX400h you can set the temperature separately for the driver and passenger. You have to go into the climate menu and you should be able to see the settings there. Hope it helps.

Sent from my Nexus 7 using Tapatalk

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Agree with Jason.

Make sure you have your climate control NOT on "dual" mode. Then check again to see if they are blowing the same temperature air out.

The dual function lets the passenger and driver set different temperatures and then, if the setting is on auto, it blows air of different temperatures on one side dependent on temperature set.

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Thanks for your reply. With dual off it has improved a little but the passenger side is still giving out somewhat cooler air then the drivers side when would assume with dual off they should be the same?

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With dual off they should be the same. Im quite baffled now.

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Me too .... Someone had suggested that it could be a flap sticking but obviously don't want to remove the dash on a trial and error basis. Was wondering if there was such a thing as a reset or weather this could be a symptom of needing re-gassing?

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55 minutes ago, Webby123 said:

Me too .... Someone had suggested that it could be a flap sticking but obviously don't want to remove the dash on a trial and error basis. Was wondering if there was such a thing as a reset or weather this could be a symptom of needing re-gassing?

That could very well be a plausible explanation but yes, removing the dash on trial and error is quite risky, especially with the amount of rattles that could potentially be created.

A re-gas might be the best way forward and its relatively cheap - should be around £50. However, Ive never re-gassed any of my cars and I was under the impression you wouldnt get cold air at all if it needed doing?

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Yes it seems to blow out plenty of air, cold one side and hot the other .... Apparently to get at some of the components you need to remove the whole dash and lower steering column 

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I doubt it needs re-gassing if its blowing cold air out of one side.  I think the warning light would be on if the gas pressure was low and there was no cooling.  I suspect its a stuck flap.  Try switching it between modes a few times to see if that will loosen it. Also try switching to recirculate and back a few times.   I think if you have to remove the dash you might be in big trouble as there are air bags under it.  If the worst comes to the worst you could just block the "hot" side off and rely on the air flow from the cold side.

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hi  just been reading the above thread most manufacturers useualy give the heating a bius to the drivers side of the vehicle

regardless of the settings you put in .hope this helps

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Thanks again for all the suggestions ..... Have messed about repeatedly with the settings to see if will loosen anything up. There is plenty of air coming out of both sides so assume that means gas is ok? It sometimes gives cooler air out of the drivers side but not quite as cold as passenger side and that's with or without dual on. Then all of a sudden the drivers side just starts pushing out hot air despite the temperature setting at the lowest and very cool air coming out of the passenger side with the dual switched off, when theoretically they should both be the same ..... Totally baffled so i suppose i need some advice from someone of some knowledge of the workings of this system?

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It could be an intermittent fault with one of the cabin temperature sensors, the on on the drivers side, no idea where they are though.

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22 hours ago, Webby123 said:

I have recently purchased a used 2008 RX400h but unfortunately the air con is not working correctly. The left hand vent will blow out hot and cold air but the right hand one only hot air, not ideal as summer approaches. I have taken it today to a reputable car electrical workshop and unfortunately his fault find machine could not connect/sync to the car so could not see if were any fault codes. I would take to Lexus but I live on Isle of Wight and the nearest dealer is Southampton. They are quoting min two hours to run diagnostics at £130 per hour and then want the car for two days to try to establish the problem which will be an uneconomical repair for a car that cost £8000.  Any suggestions as to what the problem could be and how to resolve would be greatly appreciated.

Did you buy privately or from a dealer?

If a dealer then it is his responsibility to repair/replace at his own cost.

 

Regards

 

John

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Purchased from a motor trader and the GO warranty does not cover air con and heating unfortunately. They claim it worked when collected but after an hour of ownership realised that it did not.  I paid £7500 for an 08 car with 100,000 on the clock so difficult to justify the £1000 plus Lexus are quoting to diagnose and for labour alone and expect if parts required they will not be cheap. I am just hoping that it is something that can be remedied without having to remove the whole dash.  It does seem a little unloved as the rear wiper did not work and have managed to free it up with a bit of elbow grease and WD40 so am hoping the air con is just a lack of use and may kick in property by using it and keep changing the modes.

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22 minutes ago, Webby123 said:

Purchased from a motor trader and the GO warranty does not cover air con and heating unfortunately. They claim it worked when collected but after an hour of ownership realised that it did not.  I paid £7500 for an 08 car with 100,000 on the clock so difficult to justify the £1000 plus Lexus are quoting to diagnose and for labour alone and expect if parts required they will not be cheap. I am just hoping that it is something that can be remedied without having to remove the whole dash.  It does seem a little unloved as the rear wiper did not work and have managed to free it up with a bit of elbow grease and WD40 so am hoping the air con is just a lack of use and may kick in property by using it and keep changing the modes.

The Warranty is irrelevant. The Law provides via the Sale of Goods Act and the  www.honestjohn.co.uk/faq/consumer-rights/ . Take a  look and insist that the Dealer repirs/replaces at his cost. Seek advice from Citizens Advice Bureau or a Solicitor if he wont play ball..

Regards

 

John 

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I appreciate the advice John but my problem is I traveled from the Isle of Wight to Nottingham to collect the car so dropping it back or returning is not an option and taking to the nearest Lexus dealer on the mainland isn't either.  She claims it worked on collection so it is her word against mine and she sold with a warranty albeit this is excluded. i really cannot afford a protracted and potentially expensive legal battle which I may not even win.

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This issue will become more common as these complex cars get older/worth less, exacerbated in your case by your location.   My only suggestion would be to consult an air con specialist though I doubt the IoW has many!   May be worth a look on the US site where they are more inclined to take things apart.   Ian.

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31 minutes ago, Webby123 said:

I appreciate the advice John but my problem is I traveled from the Isle of Wight to Nottingham to collect the car so dropping it back or returning is not an option and taking to the nearest Lexus dealer on the mainland isn't either.  She claims it worked on collection so it is her word against mine and she sold with a warranty albeit this is excluded. i really cannot afford a protracted and potentially expensive legal battle which I may not even win.

Steve, whether it was working or not is also irrelevant as the Law assumes that a fault occuring within 6 months of purchase was there at the time.Citizens Advice Bureau is free. Phone the Nottingham CAB and discuss matters with them.You should not pay for anything and you must not have anyone attempt to repair matters as the Dealer will then claim that what you have done has caused the problem.

Good Luck and keep us all aware of how you get on.

Regards

John

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15 minutes ago, chesterman said:

This issue will become more common as these complex cars get older/worth less, exacerbated in your case by your location.   My only suggestion would be to consult an air con specialist though I doubt the IoW has many!   May be worth a look on the US site where they are more inclined to take things apart.   Ian.

Unfortunately the only one on the Island connected up to their diagnostic equipment and the computer would not recognize the vehicle and would give no readings :-(. He said this was quite unusual as his equipment was apparently the best on offer. Without a reading he was not prepared to go any further.

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4 minutes ago, royoftherovers said:

Steve, whether it was working or not is also irrelevant as the Law assumes that a fault occuring within 6 months of purchase was there at the time.Citizens Advice Bureau is free. Phone the Nottingham CAB and discuss matters with them.You should not pay for anything and you must not have anyone attempt to repair matters as the Dealer will then claim that what you have done has caused the problem.

Good Luck and keep us all aware of how you get on.

Regards

John

Yes I appreciate what you are saying John but even with the correct advice from trading standards and CAB it will no doubt involve legal costs and I do not want to throw good money after bad. There were a few other minor issues that I can rectify myself and I suggested that they refunded me £500 and I either live with the problem or even better find a cheaper solution.

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A couple of developments ..... After experimenting I've realised that the hot air only comes when the car is running on petrol. Whilst at no throttle or low speeds and braking (running on electric motor) the air is cooler. As soon as the engine kicks in the heat comes back?

 

Also I popped in to my local garage and put it on the diagnostic machine and came up with two fault codes:

B1421   Solar Sensor Circuit (passenger side)

B1424   Solar Sensor Circuit (Drivers side)

He reset the two fault codes and didn't resolve the problem and said they may not necessarily be the problem but a place to start.

Any technical advice in this area greatly appreciated.

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Hi,

I think the solar sensors detect whether sun is hitting the dashboard so the climate control can activate a motor on each side which flips a flap to direct cool air out of the upper dashboard air vents.

It is not uncommon that the cogs on the flaps come out of alignment with those on the motors and the system (either in climate control or manual selection) can't move them.

There is a similar arrangement for something called a blend control door which is a flap that mixes cool air with hot from the engine so it can get the temp to that which you selected on the dashboard.

Unfortunately whilst some of the time stripping the components down and re-aligning the cogs can cure the issue, sometimes parts are required which can be expensive as to replace a cog usually requires the purchase of a larger unit that the cog is attached to (at more expense!) - the real expense, however, is the labour involved which can be many hours stripping the dash to pieces to get to the faulty component (and at Lexus rates £100+ an hour) soon mounts up!

Is it possible that your car qualifies for you to purchase an extended Lexus warranty, as you'd most likely be able to get the lions share of the cost covered and also peace of mind against any future issues that could occur over the next 12 months...

Hope this helps.

Chris.

Sent from my iPhone using Tapatalk

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Unfortunately my car as literally just gone past 100k miles so not acceptable for the warranty. I'm sure whatever the problem it will be something relatively simple, but the cost of labour just to get at it will probably prove cost prohibitive to me. I have found a specialist Lexus independent garage near Southsmpton who said will run it through their diagnostics for a drink .... Still cost me a day off work to get over there and the cost of ferry trip.

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On 4/25/2016 at 2:51 PM, Webby123 said:

I have recently purchased a used 2008 RX400h but unfortunately the air con is not working correctly. The left hand vent will blow out hot and cold air but the right hand one only hot air, not ideal as summer approaches. I have taken it today to a reputable car electrical workshop and unfortunately his fault find machine could not connect/sync to the car so could not see if were any fault codes. I would take to Lexus but I live on Isle of Wight and the nearest dealer is Southampton. They are quoting min two hours to run diagnostics at £130 per hour and then want the car for two days to try to establish the problem which will be an uneconomical repair for a car that cost £8000.  Any suggestions as to what the problem could be and how to resolve would be greatly appreciated.

I've had a similar problem with my RX400h.

First of all I noticed that the vent on the driver's side of the sat nav screen was blowing warm air whilst all the other vents were cold. After a month or so, all of the other vents started to blow warmer air as well. l had it re-gassed at a main dealer for £50.

A few months later, it was blowing warm air again.

I took it to a different dealer, who re-gassed it a second time but also put dye in the system to look for a leak. I ended up having to get the condensor and some pipes/valves replaced, as the dye was picked up by a UV light in these areas. The quote was £920, but I got it done under the warranty.

A year later I've noticed the same thing developing again - warm air from the vent to the right of the sat nav screen. I'm just waiting now for the rest of the vents to start blowing warm air and I'll take it back to the dealer for a look.

 

 

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On further research i have found if I press air re-circulate and air con on buttons simualtaneously at start up it displays an error code of 46. This apparently is the Air mix Damper Control Servometer Circuit (driver side) which seems to seem to be the problem I am having. Any advice greatly appreciated.

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