AC Blowing Hot Air on everything but LO - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

pooyab · 03-05-2018, 02:17 PM

The AC has been acting weird for the last two week. It seems to only blow hot air in all the settings except LO. The image attached shows it set to 65, recirculation on, and AC on. Still blows hot air, feels like 75-80. It started of being randoms, some times hot, some normal, but now it's pretty much only hot unless its at full LO.
First guess would be AC needs recharge, but the car isn't even at 15k miles yet.
Asking here before going to the dealer, because if it's an easy fix I'd rather avoid them. Thanks.

Tcoat · 03-05-2018, 02:21 PM

Sounds like a recharge to me but as you said it is really early in it's life for that. Did you do/have done any work lately that could have damaged a line?

humfrz · 03-05-2018, 02:37 PM

You might check to see if the clutch on the compressor engages when the AC is turned ON.

If not, you might check the fuse.

If the clutch engages and the unit is blowing hot air and the fuse is good, I reckon it's time to have the system checked to make sure it's charged.

humfrz

Dadhawk · 03-05-2018, 04:09 PM

Another possibility given all the electronic controls, taken from another vehicle and may have no relationship here to any form of reality but worth mentioning.

Our 2004 Suburban has electronic triple zone controls (Left Front/Right Front/Back).

It is possible for the various gates to get out of synch with the controls and have exactly what you describe happen (heat when you should have cold). There is the HVAC equivalent of the "pedal dance" you can do to get everything back in synch. I've had to do it twice in the last five years.

This is one of the reasons I'm perfectly happy with the old-school controls in the FRS.

pooyab · 03-08-2018, 02:34 PM

Quote:

Originally Posted by Tcoat

Sounds like a recharge to me but as you said it is really early in it's life for that. Did you do/have done any work lately that could have damaged a line?

Quote:

Originally Posted by humfrz

You might check to see if the clutch on the compressor engages when the AC is turned ON.

If not, you might check the fuse.

If the clutch engages and the unit is blowing hot air and the fuse is good, I reckon it's time to have the system checked to make sure it's charged.

humfrz

I'm pretty sure it engages because it was working at times before and I can hear the change in engine idle. I'll check the fuse at this point, and if it's not that then I'll just take it to Toyota since it's still under warranty anyways, either they recharge it or fix whatever is broken.

pooyab · 03-08-2018, 02:36 PM

Quote:

Originally Posted by Dadhawk

Another possibility given all the electronic controls, taken from another vehicle and may have no relationship here to any form of reality but worth mentioning.

Our 2004 Suburban has electronic triple zone controls (Left Front/Right Front/Back).

It is possible for the various gates to get out of synch with the controls and have exactly what you describe happen (heat when you should have cold). There is the HVAC equivalent of the "pedal dance" you can do to get everything back in synch. I've had to do it twice in the last five years.

This is one of the reasons I'm perfectly happy with the old-school controls in the FRS.

Did you mean the Suburban needed a resynch or your FRS?

humfrz · 03-08-2018, 02:37 PM

Quote:

Originally Posted by pooyab

I'm pretty sure it engages because it was working at times before and I can hear the change in engine idle. I'll check the fuse at this point, and if it's not that then I'll just take it to Toyota since it's still under warranty anyways, either they recharge it or fix whatever is broken.

Good plan.

Please keep us posted on what you find out.

humfrz

Dadhawk · 03-08-2018, 06:36 PM

Quote:

Originally Posted by pooyab

Did you mean the Suburban needed a resynch or your FRS?

Suburban, but thought it was at least something to check on the BRZ. My FRS has manual controls so that isn't a problem there.

asdf · 03-08-2018, 06:56 PM

Mine seems to do the same, but dependent on outside temps (reading thru the gauge cluster). I have to set my a/c to a temp close to or lower than what it is reading for outside ambient temp to get cool air through the vents.

Dyniek · 01-07-2023, 06:24 AM

Hey, did you find a solution?
I know it’s old post, but I have the same problem on my GT86 TRD from '19
The AC will blow hot Air on everything but LO, on LO it will blow really cold Air.

RZNT4R · 01-07-2023, 08:19 AM

Stop with the A/C recharge and blend door nonsense. A bit of logic guys, if it's cold on low, and can change from cold to hot, A/C is fine and blend doors are fine.

The way an automatic AC system works is you give it a temperature target and it tries to bring the interior air temp to that target, except on low where it's target becomes "fuck everything go as cold as possible". If it's trying to hit a temperature target that means there's a temperature sensor in the system, and when temperature sensors fail, they typically fail to -48 degrees Celcius. If the automatic A/C is trying to warm you up no matter what temperature you ask of it, it may be because it thinks you're cold.

Easy diag. Read auto A/C DTCs and live data for interior temp. Continue troubleshooting accordingly.

03-05-2018, 02:17 PM	#1
pooyab Junior Member Join Date: Jan 2018 Drives: 2016 FRS RS 2.0 Location: Bay Area Posts: 8 Thanks: 0 Thanked 3 Times in 2 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	AC Blowing Hot Air on everything but LO The AC has been acting weird for the last two week. It seems to only blow hot air in all the settings except LO. The image attached shows it set to 65, recirculation on, and AC on. Still blows hot air, feels like 75-80. It started of being randoms, some times hot, some normal, but now it's pretty much only hot unless its at full LO. First guess would be AC needs recharge, but the car isn't even at 15k miles yet. Asking here before going to the dealer, because if it's an easy fix I'd rather avoid them. Thanks. Attached Images

03-05-2018, 02:21 PM	#2
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,845 Thanks: 61,656 Thanked 108,284 Times in 46,456 Posts Mentioned: 2495 Post(s) Tagged: 50 Thread(s)	Sounds like a recharge to me but as you said it is really early in it's life for that. Did you do/have done any work lately that could have damaged a line? __________________ Racecar spelled backwards is Racecar, because Racecar.

03-05-2018, 04:09 PM	#4
Dadhawk 1st86 Driver! Join Date: Feb 2012 Drives: '13 FR-S (#3 of 1st 86) Location: Powder Springs, GA Posts: 19,815 Thanks: 38,825 Thanked 24,939 Times in 11,376 Posts Mentioned: 182 Post(s) Tagged: 4 Thread(s)	Another possibility given all the electronic controls, taken from another vehicle and may have no relationship here to any form of reality but worth mentioning. Our 2004 Suburban has electronic triple zone controls (Left Front/Right Front/Back). It is possible for the various gates to get out of synch with the controls and have exactly what you describe happen (heat when you should have cold). There is the HVAC equivalent of the "pedal dance" you can do to get everything back in synch. I've had to do it twice in the last five years. This is one of the reasons I'm perfectly happy with the old-school controls in the FRS. __________________ Visit my Owner's Journal where I wax philosophic on all things FR-S Post your 86 or see others in front of a(n) (in)famous landmark. What fits in your 86? Show us the "Junk In Your Trunk".

03-08-2018, 06:56 PM	#9
asdf Loading...████████] 99% Join Date: Jul 2013 Drives: #0517 Location: southern california Posts: 586 Thanks: 227 Thanked 251 Times in 171 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Mine seems to do the same, but dependent on outside temps (reading thru the gauge cluster). I have to set my a/c to a temp close to or lower than what it is reading for outside ambient temp to get cool air through the vents. __________________ R1 3 5 ╘┼┼┤ . 2 4 6

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03-05-2018, 02:37 PM	#3
humfrz Senior Member Join Date: May 2013 Drives: 2013 FR-S, white, MT Location: Puyallup, WA Posts: 29,873 Thanks: 28,793 Thanked 31,828 Times in 16,430 Posts Mentioned: 708 Post(s) Tagged: 2 Thread(s)	You might check to see if the clutch on the compressor engages when the AC is turned ON. If not, you might check the fuse. If the clutch engages and the unit is blowing hot air and the fuse is good, I reckon it's time to have the system checked to make sure it's charged. humfrz

01-07-2023, 06:24 AM	#10
Dyniek Member Join Date: Dec 2022 Drives: Toyota GT86 TRD '19 Location: Poland Posts: 11 Thanks: 4 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Hey, did you find a solution? I know it’s old post, but I have the same problem on my GT86 TRD from '19 The AC will blow hot Air on everything but LO, on LO it will blow really cold Air.

01-07-2023, 08:19 AM	#11
RZNT4R Professional Mechanic Join Date: Apr 2010 Drives: 2017 86 6MT Oceanic Location: Quebec, Canada Posts: 789 Thanks: 17 Thanked 633 Times in 371 Posts Mentioned: 12 Post(s) Tagged: 0 Thread(s)	Stop with the A/C recharge and blend door nonsense. A bit of logic guys, if it's cold on low, and can change from cold to hot, A/C is fine and blend doors are fine. The way an automatic AC system works is you give it a temperature target and it tries to bring the interior air temp to that target, except on low where it's target becomes "fuck everything go as cold as possible". If it's trying to hit a temperature target that means there's a temperature sensor in the system, and when temperature sensors fail, they typically fail to -48 degrees Celcius. If the automatic A/C is trying to warm you up no matter what temperature you ask of it, it may be because it thinks you're cold. Easy diag. Read auto A/C DTCs and live data for interior temp. Continue troubleshooting accordingly.

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