foreste1

Ok, I have been struggling with this ac problem for 2 summers now and dont want to have it this summer again. I am in Phoenix and my a/c is ice cold most of the year when idling or driving, both front and rear. Last 2 summers when I get stuck in traffic for too long when temp outside gets up close to 95 and upwards the cold air will turn musty warm and almost has a sweet smell to it (not leaking antifreeze) and then if I move the car a few feet it will go to ice cold again, and stay cold if I am moving. I had the system evac and recharged couple months back just to try and be ahead of the problem this year. I also replaced the condenser fan (it was fine though). Its been so cold I thought it was good until yesterday. I was sitting for 10 minutes or so and it was about 95 outside and here comes that warm air again and that musty smell (humid).
Once I moved car a few inches it went cold again. I also replaced the mag clutch relay 3 summers ago, and I dont see any ac light blinking on dash when problem occurs.

I am having my dash replaced next week at Lexus and asked what it would cost to replace expansion valve since its in the dash, figuring maybe that is it, but they want $550 just labor to replace it, seems really high and I am not sure that is it anyway. Any ideas?
Could it be a blend door issue opening up and letting warm air in and then closes once I move? Receiver dryer? Compressor works great, and again its ice cold most of the year and the back a/c works well also except when this problem occurred yesterday the rear was warm as well.

On other thing I have noticed while driving the last few months with a/c on (you need a/c here year round but temps maybe in high 80's) I can feel ice cold air blowing and then just a slight bit of warm air for a second or so and then back to ice cold, this is while I am driving. not idling. Most passengers in car cant tell, but I know its happening almost constantly.

I dont want to take to just another mechanic as they never really know what it is and say its different things each time (evac/recharge, condenser fan etc) all wrong. Lexus says 175 to diagnosis, just thinking maybe somebody knows before I have them do it.

foreste1

Also I dont notice difference form drivers side to passenger side of car, both sides are either warm or cold. Also I dont seem to have heat this winter when I went up to mountains, no idea if related.

foreste1

Last thing reading on other threads about ac door broken after replacing ac filter, but they are talking about and IS Lexus, hoping mine does not have that same bad set up? I have changed my cabin filter before, but not sure if I had it in recirc mode as these other threads talk about, but again they are talking about different Lexus model.

foreste1

Last thing reading on other threads about ac door broken after replacing ac filter, but they are talking about and IS Lexus, hoping mine does not have that same bad set up? I have changed my cabin filter before, but not sure if I had it in recirc mode as these other threads talk about, but again they are talking about different Lexus model.

foreste1

Servo maybe, again reading about many people with no heat in winter same as me and thinking servo motor needs cleaned or replaced or arm broken off that changes flap? But I dont hear any ticking noise under dash but starting to think servo bad? Is it on passenger side under glove box?

foreste1

Ok I pulled out the glove box and I can see an arm working perfectly when I change from hot to cold setting on temp for both sides of car. I also took off rear panels to rear ac, but do not see anything out of ordinary there (thought maybe a filter to change out).
Now I ran the A/C check and it comes up with codes:
21
24
42
Not sure why 21, it was outside in direct sunlight.
24, what is that? I dont see a 24 on any codes on internet??
42, air inlet door servomotor circuit, could this be what is wrong and causing no heat (or just slightly warm air in winter) and now causing the system to go from ice cold to luke warm and back to cold when driving and going from cold to luke warm when idling in high exterior temps? If so anybody know where this part is and a part # to replace along with DIY?

foreste1

Sorry so many posts today but I have been hunting this problem down. I am really starting to believe its the code 42, air inlet door servomotor. However I did see behind glove box when I adjust from hot to cold temp that one seems to work just fine unless maybe it gets stuck intermittently? Also is there only 1 or is there another one on drivers side? I have read so may threads today, but not one is on the GX and how to replace thees, anybody have that thread?

foreste1

Last idea I have, could it be the ac evaporator temp sensor? Wondering because this issue only happens when it gets pretty hot outside above about 95 degrees when its cooler outside like 85 degrees I can let the truck idle for 2 hours and ac stays ice cold, just when it gets hotter outside this all starts again. I found that part number 88625-16210, but cant figure out where it is located to change out? Seems like either a inlet door servo or this evap sensor. I dont hear any weird noises under dash when switching from heat to cold likes some describe when its a servo motor. I also ran the diag on the dash through all 10 flapper door changes and going from defrost to feet and to rear or car etc, it all seemed to work well. I also dont notice one side of car being any different than the other. Whole car goes warm at same time and back to cold.
If you cant tell, this is driving me crazy until I fix it!
Thanks for any help here.

dkpnkc

Not an expert but found a couple threads:
https://www.clublexus.com/forums/mai...c-at-idle.html
http://us.lexusownersclub.com/forums...-all-the-time/

foreste1

I am going to move my last findings to new thread to spare everyone reading so much!