I've been trying to look for a solution for this along with my mechanic for the past couple months now. When I start the car the AC system will take about 2 minutes before turning on and allowing all the controls to function. Once it is on, it blows cold and functions as it should with no issues. If I shut the car off and turn it on right away, the AC has no issues turning on right away. However, if I leave the car off for maybe more than 5 minutes, it seems to reset and the same thing happens again and AC delays for 1-2 minutes. I've read somewhere it may be something to do with the coolant for some reason? I did realize it was a little low on coolant in the reservoir a while back which I topped off and it took away that waterfall noise coming from inside the cabin but AC system still behaves the same way. I have also read some have tried complete flush of the coolant and that seemed to work for them. My mechanic said the coolant isn't directly correlated to the AC and it most likely is whatever device sends signal to the AC to start up. Does anyone have any thoughts?

 

I think you need to consult a refrigeration technician. This may be related to overcharge or undercharge of the refrigent.

 

I'll take that into consideration, thanks! Didn't think it would play a factor since the AC is ice cold once it's on. But then again it has been taking a couple seconds to blow cold from cold start lately, I've just been attributing it to the warmer weather.

 

A number of us have had this problem. Replacing what is called the ac amplifier was the fix. The ac amplifier is a computer that controls the ac system. I picked a used one up on ebay for around $50. I replaced it approximately a year ago with no problems since. It's located near the passenger foot well area.

 

What was you problem ? I think the amplifier also control the blend doors right ?

 

NICE, thanks for the plug! That would be a quick and cheap fix if it does work, I'll have to give that a try asap.

 

Here is another thread. I copied what I wrote in that thread and pasted below. https://www.clublexus.com/forums/ls-...perhaps-2.html
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My 07 460 had a similar issue. Only cold air out the passenger side. Drivers side had no air flow. It also reset to 75 degrees on engine start up after about 1 minute.

I tried to take as little apart as possible to reach it. I only remember it being a tight fit to swap it out. You must have taken more apart than I did to check pins. If I had to guess I would say my harness had some slack, maybe an inch or so.

If my car's ac system was working correctly when the car started it continued to function correctly until I shut the car off. The ac system started acting up 1 month before I decided to replace the amplifier. My temporary fix during that month was to restart the car if the ac failed to operate correctly. It progressively got worse, almost every start or restart resulted in the ac temp resetting to 75 followed by random ac faults. Sometimes it would only blow cold out the lower vents. Sometimes only the passenger side. It was 115f during the summer here when it started acting up.

 

Thanks, reading through it. I just ordered a used amplifier for $40 so I'll be a happy camper if that will be the fix. That's pretty much the last issue I have on the car aside from the rear AC on the B pillar and behind the center console not blowing any air. Will wait for that amplifier to see if that fixes anything in the rear before diving deeper into those.

 

Quick update:
I received the used amplifier I ordered from eBay and swapped it out. Turns out that I got the wrong part number-- it's for a SWB and I have an LWB model(did not have the extended climate controls on the touchscreen when you go to the climate settings). Part number I ordered was 88650-50440 but what I need is 88650-50450. Can't seem to find it anywhere so I'm going to see if my mechanic can source it or just find out how much Toyota has it for. My only concern is that when I swapped it out, there was still a delay in the AC startup. Not sure if the amplifier I got is bad as well or if it's because I got the wrong part but I'm hoping it's either of these or else I have a different issue than what others are experiencing.

 

It's hard to say you may have another issue. Is your blend door opening and closing normally when you view it in the glove box? I've read that can cause the delay if it is not functioning correctly. I'd probably still try the correct ac amp first.

Is your temp resetting to 75f after the delayed ac starting up?

 

Blend door functions normally, swapped out the filter not too long ago and made sure the blend door was in the open position before attempting the swap. Yea, when it finally turns on, it either starts up at 75f or "air conditioning off."

Got a quote from my trusted mechanic for the part I need since I can't find any used ones online. It's no longer available at Toyota and it is special order from Lexus for $650. Wasn't prepared to shell out the cash since I'm not 100% sure the amplifier is really my issue so I'm going to try pick-your-part to see if I can find a cheaper replacement.

 

I got the ac off message on occasion too before I swapped the amp out.

 

I had same problem i fix it by taking dash apart and replace servo motor wiring 😅

 

Awesome, this gives me hope. I'm still going to try and find a pick-your-part since I've swapped the part twice already on my car, haha.

I had read about the servo motors as well. But when I brought it up to my mechanic he mentioned it's more likely whatever controls the startup of the AC.

 

I have a similar problem with my 2009 LS 460. Anytime I start the car after 15 minutes rest it takes about a minute to give me the AC Off. When I hit the Auto button it always starts at 75 degrees unless I start the car within 15 minutes then everything works as it should. So do I replace the AC amplifier? After reading this thread I priced one at the Toyota dealer at $750.00. That is a lot to pay if that does not fix the problem. Thanks for any help!