why AC compress engaged when I switch to blow warm air to windshield.

[Fareastplaza]

I didn't notice this during summer. But now in winter here, when I start turning on heat/warm air, I notice other settings are working fine, but when I switch the setting to let warm air blow to the front windshield, I can hear the A/C compressor has been engaged as my AC compressor currently doesn't work and make a big noise. I know it is bad, I just don't want to fix it during the winter as I don't need it. But why it is engaged when in this one setting? I am sure I didn't turn on AC at all, and only warm air came out.

 

[comtn4x4]

I didn't notice this during summer. But now in winter here, when I start turning on heat/warm air, I notice other settings are working fine, but when I switch the setting to let warm air blow to the front windshield, I can hear the A/C compressor has been engaged as my AC compressor currently doesn't work and make a big noise. I know it is bad, I just don't want to fix it during the winter as I don't need it. But why it is engaged when in this one setting? I am sure I didn't turn on AC at all, and only warm air came out.

When selecting air to the windshield it's activating your defroster/dehumidifier. In order to work properly it turns on the AC to aid in dehumidifying.

 

[Jetboy]

FWIW - If you want to wait until summer to fix your AC compressor, you could disconnect the wiring to the AC clutch for a temporary disable. Easiest way to do this is to pull the fuse. It's under the hood IIRC in the fuse block there and probably marked A/C. That might get you through winter until you can fix in spring.


Good luck.

 

[cbreze]

Not sure about newer rigs but in my 2012 SR5 there is a setting one notch back from full defroster. I believe it divides the flow between floor and windshield. In this position the AC does not turn on. I use it frequently in winter. It puts an adequate amount of air on the windshield.

 

[Golfpilot]

There is nothing to repair, seems to be normal. as soon as the fan is switched on and one of the two windshield positions is selected, the air conditioning compressor runs. i have also recently investigated:
Condensate water even with AC off?

 

[Golfpilot]

I would also prefer a different behavior, most of the time airflow to the windshield is enough without air conditioning. I don't want to drive with air conditioning all the time.

 

[Fareastplaza]

Not sure about newer rigs but in my 2012 SR5 there is a setting one notch back from full defroster. I believe it divides the flow between floor and windshield. In this position the AC does not turn on. I use it frequently in winter. It puts an adequate amount of air on the windshield.

Can you explain more about this? Do you mean there is a button can do this?

 

[Golfpilot]

I think it means the foot + windshield position, but my 2019 TRD Offroad Premium engage AC in both positions:

 

[cbreze]

I think it means the foot + windshield position, but my 2019 TRD Offroad Premium engage AC in both positions:

Yes, this is what I meant. You explained it a bit better. my SR5 being a 2012 model year apparently works differently then the newer models in this regard.

 

[Fareastplaza]

I think it means the foot + windshield position, but my 2019 TRD Offroad Premium engage AC in both positions:

[MENTION=727058]Golfpilot[/MENTION], unfortunately, on my 2010 limited, both setting will have AC kicked in. Maybe the best way is to disable the compressor by pulling out the fuse.

 

[Fareastplaza]

FWIW - If you want to wait until summer to fix your AC compressor, you could disconnect the wiring to the AC clutch for a temporary disable. Easiest way to do this is to pull the fuse. It's under the hood IIRC in the fuse block there and probably marked A/C. That might get you through winter until you can fix in spring.


Good luck.

Will it cause any problem without AC to dehumidify the air? I am worried it actually fog the windshield even worse?

 

[mbm112]

Will it cause any problem without AC to dehumidify the air? I am worried it actually fog the windshield even worse?

Generally warm air alone is enough to defog, it’s just that A/C helps speed up the process and removes moisture from the air in the car to help prevent from fogging back up.


Sent from my iPhone using Tapatalk

 

[DAW89446]

Running the AC compressor during defrost cycle has been the norm in vehicles for years. As mentioned, it helps dehumidify the air and speeds up defrosting. Running the compressor while defrosting also keeps the AC system from just sitting for months on end; which can cause seals to dry out, and premature failure of the compressor.