AC occasionally doesn't work on 09
09-05-14, 01:57 PM
#1
AC occasionally doesn't work on 09
I purchased an 09 RX350 about a month ago. The car is in excellent shape with 97k miles and is the pebble beach edition. The AC worked perfect of course at the dealer and I did drive it quite a bit before purchasing it. Two weeks later on my way home one day the AC wasn't blowing cold. Got home and turned the car off and restarted it and it instantly started blowing cold. Didn't think too much of it then because I thought maybe I had pressed the AC button on accident. That was two weeks ago and the air has been super cold ever since. Today however on my way home the air wouldn't blow cold again. Get home and with the car still running I make sure the AC button is on which it is. Air on its lowest setting and it isn't cold at all. The electric fans would go on when I pressed the AC button and then off when I turned the AC off. Thought maybe the fans weren't working and the car wasn't letting the AC turn on but that isn't it. So I turned the car off and let it sit for a couple minutes. Turn it back on and the AC is working perfect. Any body have any ideas about what could be wrong before I bring it in to the dealer? My coolant level is spot on. Also on both occasions the air didn't cut out half way through my drive home. It just didn't work from when I started the car. Kinda has me puzzled. I had a 2000 GS400 with 220k miles and never once had a problem with the AC.
09-05-14, 04:56 PM
#2
Lexus Champion
Have you checked the battery? The computer starts shutting things down if there are power bobbles. If you don't know the history of the battery I wold replace it even if it checks out. I would never risk a no start over a hundred dollar battery. YMMV
09-05-14, 05:10 PM
#3
The battery isn't the original Lexus one the car would have come with. The battery has a sticker on it that has the date 11/12 on it. So the battery is a little less then two years old. The car has always started fine and never acted like it was struggling. I think the car would be shutting down more than just the AC if the battery was weak.
09-05-14, 06:52 PM
#6
Lexus Champion
The battery isn't the original Lexus one the car would have come with. The battery has a sticker on it that has the date 11/12 on it. So the battery is a little less then two years old. The car has always started fine and never acted like it was struggling. I think the car would be shutting down more than just the AC if the battery was weak.
Last edited by Carver; 09-05-14 at 07:50 PM.
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09-06-14, 10:42 AM
#8
Battery is fool's gold. Battery voltage level will have little to do with A/C performance once car is started as the entire car runs off alternator once started.
Check the following:
Freon levels. If Freon too low or Hugh system will shut off.
Sight glass bubbles.
Make sure A/C clutch is engaging when you press the A/C on. - clutch is middle part of a/c pulley that WILL NOT MOVE WHEN A/C off.
MAKE SURE COOLING FANS IN FRONT OF RADIATOR ARE BLOWING WHEN A/C IS ON. These can fail intermittently and when they are not on system won't cool air efficiently.
Servo motors are working properly when your air output switched properly when changing from vents to floor to defrost etc. Unlikely that outside air blend vent is malfunctioning unless you cannot tell a difference when pressing the button from air output.
Check the cabin filter.
My guess: a/C freon levels or A/C compressor OR Engine Cooling Fan Motors malfunctioning. NOT THE INSIDE VENT FAN MOTOR SO DO NOT CONFUSE. That fan is working if air is coming out of vent.
Check the following:
Freon levels. If Freon too low or Hugh system will shut off.
Sight glass bubbles.
Make sure A/C clutch is engaging when you press the A/C on. - clutch is middle part of a/c pulley that WILL NOT MOVE WHEN A/C off.
MAKE SURE COOLING FANS IN FRONT OF RADIATOR ARE BLOWING WHEN A/C IS ON. These can fail intermittently and when they are not on system won't cool air efficiently.
Servo motors are working properly when your air output switched properly when changing from vents to floor to defrost etc. Unlikely that outside air blend vent is malfunctioning unless you cannot tell a difference when pressing the button from air output.
Check the cabin filter.
My guess: a/C freon levels or A/C compressor OR Engine Cooling Fan Motors malfunctioning. NOT THE INSIDE VENT FAN MOTOR SO DO NOT CONFUSE. That fan is working if air is coming out of vent.
09-06-14, 11:18 AM
#9
Battery is fool's gold. Battery voltage level will have little to do with A/C performance once car is started as the entire car runs off alternator once started.
Check the following:
Freon levels. If Freon too low or Hugh system will shut off.
Sight glass bubbles.
Make sure A/C clutch is engaging when you press the A/C on. - clutch is middle part of a/c pulley that WILL NOT MOVE WHEN A/C off.
MAKE SURE COOLING FANS IN FRONT OF RADIATOR ARE BLOWING WHEN A/C IS ON. These can fail intermittently and when they are not on system won't cool air efficiently.
Servo motors are working properly when your air output switched properly when changing from vents to floor to defrost etc. Unlikely that outside air blend vent is malfunctioning unless you cannot tell a difference when pressing the button from air output.
Check the cabin filter.
My guess: a/C freon levels or A/C compressor OR Engine Cooling Fan Motors malfunctioning. NOT THE INSIDE VENT FAN MOTOR SO DO NOT CONFUSE. That fan is working if air is coming out of vent.
Check the following:
Freon levels. If Freon too low or Hugh system will shut off.
Sight glass bubbles.
Make sure A/C clutch is engaging when you press the A/C on. - clutch is middle part of a/c pulley that WILL NOT MOVE WHEN A/C off.
MAKE SURE COOLING FANS IN FRONT OF RADIATOR ARE BLOWING WHEN A/C IS ON. These can fail intermittently and when they are not on system won't cool air efficiently.
Servo motors are working properly when your air output switched properly when changing from vents to floor to defrost etc. Unlikely that outside air blend vent is malfunctioning unless you cannot tell a difference when pressing the button from air output.
Check the cabin filter.
My guess: a/C freon levels or A/C compressor OR Engine Cooling Fan Motors malfunctioning. NOT THE INSIDE VENT FAN MOTOR SO DO NOT CONFUSE. That fan is working if air is coming out of vent.
The cooling fans were working just fine when the car wasn't blowing cold air. The fans would come on when the AC button was on and the fans would go off when the AC button was off.
Everything works when I change from defrost to floor vents to the face vents and I can tell a difference when I cycle between the air recirculation.
I changed the cabin filter the day I bought it which was a month ago.
The AC compressor was engaging and disengaging when I would press the AC button.
Drove the car some this morning and the AC was working just fine. Has me stumped. Normally when I have experienced AC problems on cars it has been much more frequent then every two weeks.
09-06-14, 11:08 PM
#10
Check the cabin temp sensor. It is below the steering wheel just to the right and has a square vent like covering I I recall correctly. It can get dust and build up on it which effects air temp and the blend of outside and inside air.
Also have your levels checked. If freon is low, it would be less efficient on hot days or cold days.
I had this same issue twice. Once was freon levels. One time I had a cooling fan that the connector from the fan ECU to the fan motor was faulted and would cause the fan to work intermittently.
Also, see if the problem tends to arise when you are stopped or at an extended stand still. Then resolves itself once the car is moving. This is a fan related issue if so.
Also have your levels checked. If freon is low, it would be less efficient on hot days or cold days.
I had this same issue twice. Once was freon levels. One time I had a cooling fan that the connector from the fan ECU to the fan motor was faulted and would cause the fan to work intermittently.
Also, see if the problem tends to arise when you are stopped or at an extended stand still. Then resolves itself once the car is moving. This is a fan related issue if so.
09-07-14, 06:52 PM
#11
Check the cabin temp sensor. It is below the steering wheel just to the right and has a square vent like covering I I recall correctly. It can get dust and build up on it which effects air temp and the blend of outside and inside air.
Also have your levels checked. If freon is low, it would be less efficient on hot days or cold days.
I had this same issue twice. Once was freon levels. One time I had a cooling fan that the connector from the fan ECU to the fan motor was faulted and would cause the fan to work intermittently.
Also, see if the problem tends to arise when you are stopped or at an extended stand still. Then resolves itself once the car is moving. This is a fan related issue if so.
Also have your levels checked. If freon is low, it would be less efficient on hot days or cold days.
I had this same issue twice. Once was freon levels. One time I had a cooling fan that the connector from the fan ECU to the fan motor was faulted and would cause the fan to work intermittently.
Also, see if the problem tends to arise when you are stopped or at an extended stand still. Then resolves itself once the car is moving. This is a fan related issue if so.
I'll probably make an appointment this week at Lexus and see if its low on freon.
Doubt its the fans. Like I said they were both on when I had the AC on. Unless the car didn't think they were on and was not letting the AC come on.
Doesn't seem to make a difference if I am stopped idling or while the car is moving.
04-16-15, 07:42 AM
#13
Checked the temp sensor. It had a little bit of dust on it but wasn't that bad.
I'll probably make an appointment this week at Lexus and see if its low on freon.
Doubt its the fans. Like I said they were both on when I had the AC on. Unless the car didn't think they were on and was not letting the AC come on.
Doesn't seem to make a difference if I am stopped idling or while the car is moving.
I'll probably make an appointment this week at Lexus and see if its low on freon.
Doubt its the fans. Like I said they were both on when I had the AC on. Unless the car didn't think they were on and was not letting the AC come on.
Doesn't seem to make a difference if I am stopped idling or while the car is moving.
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