New issue with my 2005 LS430 ultra, 155k miles... A/C starts out warm on right side. Seems to affect rear ceiling vents (ultra only) as well, but especially noticeable in front passenger seat. (Ice cold out of driver's side after just a minute) Eventually it sees to cool down after perhaps 20 minutes, but not quite fully, I think... (Yes, I have tried adjusting the temperature, including putting a/c to "cold" (lowest) separately on both sides.)

I will have to take it in somewhere, but wondering if low coolant could cause this. 5 years ago when water pump went bad, A/C stopped blowing cold until fixed, but I figured that was protective mechanism to help minimize overheating. Could low coolant somehow affect performance of A/C on on side? I figure that's more likely with heat.

I have had a years-long issue where I have no coolant showing in overflow tank. Dealer could not identify issue, and car has never overheated in 5 years, and radiator has never been low in coolant despit the overflow tank. But wondering if low coolant condition could cause this. I am due after 5 years to change coolant anyway, but I might just top off (fill, really, as it shows empty) overflow tank first and see if that helps...

Since the air evemtually eventually (kind of) cools down, I am thinking it is not just bad blend door servos or what not....But then, what?

I realize just now that I have not played with mode (recirc vs external air) to see if that makes any difference. I'll try it in heat tomorrow.

Any suggestions appreciated. I am hoping the whole dash doesn't need to be gutted to get to any actuators...

I always heard that special refrigerant line to the rear a/c could fail in the ultra,, and it is expensive, but this right/left split thing (even when both sides are on max cold) caught me by surprise. My wife first noticed it as a passenger.

Also, do people think an independent mechanic is a good candidate to tackle this?

 

Warm air out of the passenger vents is a very common indication in a freon leak. I'd start with having the freon measured and if low, have them add dye and check to see where your leak is. I'd also suggest using a thermometer to check actual vent temps for both sides.

 

I don't know if the LS430 is the same, but on my old ES330, the blend door actuator was located right beneath the glove box, right around where the passenger's left knee would be. I only had to remove 1 trim panel from beneath the glove box to access the actuator. Only took me about 20 minutes to replace, and the actuator itself was about $30 on amazon. In my car, the plastic gears on the actuator were wearing down, so it would work occasionally, but it eventually stopped working all together. I could also hear a faint clicking noise coming from the actuator when I turned on dual zone and adjusted the temperature on the passenger side. It might be worth taking a look at.

 

Thanks. I am thinking it is not the blend doors, as I can warm and cool the vent fine by adjusting the temperature, but it just doesn't get fully cold: coolest feels "unrefrigerated". Also I now remember my old car had an issue like this years ago when a hose went bad... Mechanic spotted it and replaced it and that fixed it. Not sure if he needed to re-add refrigerant.

 

Thanks. Very obvious on a hot day, less obvious with cooler weather.

 

Mine is the opposite. Warm on left, cool on right. Is there another actuator on the left side?

 

I'm not actually sure. From looking at LexusPartsNow, there are left and right handed versions of the actuator that I bought for my ES330, both labeled "For Airmix". But for the LS430, I only see 1 actuator labeled for Airmix. THIS looks like it might be the right part, but it's labeled "For Mode", so I don't know for sure. Either way, If you can find the correct part number, I'd suggest ordering a compatible part number on Amazon/Ebay instead of paying full price for it from a dealer. I paid $30 for it on amazon, compared to like $180 from a dealer. Might not last as long as OEM, but I wouldn't mind replacing it again for 1/6 of the price.

 

I was checking for parts on the Autozone site and found the right side actuator with a diagram exploded view of where it’s located.

I then called because I couldn’t find the other side. I was told there is the right side one and a “main” actuator. They don’t have the diagram. What do you think? It has to be ordered while I’ll check Amazon first.

I’m kind of hoping someone has a shop maintenance manual to check it out.

I’ll check the link you put in the thread. Thank you!

Dianne