LS430 - More Air Conditioning Anomalies

[DomTurner]

I've noticed an issue recently in which the air coming out of the passenger vents (including the left centre one) feels considerably cooler than the air from the driver's side (including right centre) even though the set temperature for both sides remain the same - 19 degrees. 

I have tried to change temperatures up and down with buttons & voice control and it still happens. Closing the left centre vent will send more air through the right one but doesn't appear to be any cooler, but when opened again you can immediately feel the difference between the two which has confused me. I know the car sends more air into "hot spots" of the car when the oscillating vents are enabled so I also thought could this be the car sending cooler air to everywhere but the driver? I have not yet remembered to test it with a passenger onboard.

Image of the current climate settings is below (yes I know it needs a little clean):

[MLW]

As a thought, maybe disconnect the Battery for 2 hours, reconnect and see if it improves. Unlikely, but cheap and worth a try.

[DomTurner]

Bumping this topic as I'm still having issues.

All front vents now blow air that doesn't feel that cool, with the furthest left one being the coolest and the other 3 being a lot warmer. The rear vents (top and centre) are blowing what feels like proper A/C...
I ran the Auto & Recirc button diagnostic and no codes are showing up.

Because the rear feels fine I think it may be a cabin air sensor issue but after opening up the vent (just above the handbrake release) and cleaning what dust there was, it hasn't made a difference so I'm not sure it can be that either.

I don't really know what to try next, I've been told it could be leaking refrigerant but the code I had before when it was empty (23) is not showing at the minute and the place that leaks the most is the rear A/C lines but the rear A/C is completely fine.

... I'm lost.

[Herbie]

It could be a mixer flap seized or low refrigerant.

[DomTurner]

1 hour ago, Herbie said:

It could be a mixer flap seized or low refrigerant.

Thanks for the ideas, I forgot to mention that I spoke to Paul Frost from LexusPartsDirect and he told me that there is only one blend door actuator so I don't think it's that - unless he thought I meant a different part, not sure of the part no or where it is.

I suppose the best bet is taking it to an air con specialist and let them have a look for leaks that the previous place may have missed.

[cruisermark]

I have done some googling on this and found that this is a common problem on the LS and GS.

I haven't found a definative answer however the following seem to be the areas where the problem could lie:

• Low coolant
• Blocked matrix
• Faulty/seized air blend flap

If I find anything concrete I will update

[Stanwithaplan]

One side had failed completely when I bought my LS400, had to replace the compressor, cost equivalent of £570 including fitting, cleaning and regas :o(  

More recently the entire aircon struggled if left parked in the heat, took ages to get "cool/tepid", I replaced the condensor with a GCC spec one (to cope with hot climates) cost £196 including fitting, flush and regas, it is flipping freezing within a couple of mins now, nice.

[Malc1]

On 11/5/2022 at 7:26 PM, Stanwithaplan said:

the entire aircon struggled

mine's not worked cooling since just after i bought her ......  11 years back .........  I'm ok opening windows tbh

Malc

[DomTurner]

Reviving this once again after some nice weather. Recently my coolant levels were fairly low so I've topped up to the "Max" fill line and it has made quite a difference to the air coming out of the vents. It isn't ice cold like when the A/C is working properly but a lot cooler than it was.

After going through the A/C self-diagnostic it is giving me codes 21, 24 and 28 which all relate to the driver, passenger and rear solar sensor. This was at midday on a bright day - should these still be showing even when it is that bright outside? Could this be anything to do with the issues I am getting or do they just control the "Auto" functions?

Just thought I'd ask before going to an A/C specialist.

Thanks.