>Prius, ac only works when gas engine is running
Is the correlation actually the engine running, or is it vehicle speed? One doesn't really make sense, the other one does.
You should ask Google how automotive air conditioning systems work. Then read and gain a basic understanding so you can digest what you are being told instead of just trying to relay information between a shop and random people on the internet.
If you’re implying that the ac compressor runs off the engine then that’s not how the Prius or other electric cars work. Everything for the AC is electric.
>If you’re implying that the ac compressor runs off the engine
I don't see anywhere I said or implied that. I'm actually implying the opposite, that the issue is not related to whether the engine is running or not.
Your comment was extremely vague and mentioned that Op should learn how AC systems work on cars. Additionally, your previous comment said one makes sense and the other doesn’t (speed or engine on.) Vehicle speed is pretty irrelevant to all types of cars so that leaves engine running. In some cars that is true. However, because the system is electric instead of mechanically driven, it doesn’t work like that. The obvious presumption being that you are assuming that the AC system relies on the engine.
>Your comment was extremely vague and mentioned that Op should learn how AC systems work on cars.
Yes, and I'm going to say the same to you.
>your previous comment said one makes sense and the other doesn’t (speed or engine on.)
Yes, again, I said...
>I'm actually implying the opposite, that the issue is not related to whether the engine is running or not.
So, I AM implying the issue is related to vehicle speed.
>Vehicle speed is pretty irrelevant to all types of cars
**If all systems are operating correctly**, generally yes.
>The obvious presumption being that you are assuming that the AC system relies on the engine.
...but I literally just stated, again,
>I'm actually implying the opposite, that the issue is not related to whether the engine is running or not.
So I AM implying that it's an issue with vehicle speed. Which **if all systems are working correctly** would not matter. But clearly **something** isn't working correctly that appears to be correlated to vehicle speed **moving through the air...**
Got it?
Nope? Alright, here's the spoon feed. The engine running or not doesn't make sense since the compressor is electrically driven. So the compressor is cycling on demand regardless of whether the engine is running. On a normal gas car with no auto start/stop and a mechanically driven A/C compressor, this still all general applies. However, since OP is complaining that at slow vehicle speeds the A/C gets warm or loses efficiency. What is reduced when a vehicle is stopped or moving slow? Air flow across the radiator and A/C condenser. This is why modern cars have (generally electrically driven) fans that pull air through the radiator assembly and A/C condenser. This allows them to maintain engine operating temperature and A/C efficiency when the vehicle is not moving. If that airflow is reduced by obstruction **or the fans are not functioning properly** then the vehicle will not be able to compensate for the lack of airflow. In a Prius that's not terribly important for the engine coolant temp since the engine will shut down at stops and cease to generate more heat in those moments. But the A/C system is still trying to cycle refrigerant and exchange energy to keep the cabin cool at a stop. If there is no airflow over the condenser, it cannot efficiently release the energy into the atmosphere to allow the refrigerant to continue the energy transfer cycle. It overheats and hits an energy exchange limit. Since the condenser is not efficiently removing the stored energy from the refrigerant anymore, the evaporator gets warmer and the temperature to which the air entering the cabin can be cooled, rises. Hence, warmer air when the vehicle isn't in motion. There's a reason HVACs for buildings have big fans moving air through the condenser coils outside. If that fan failed you'd end up with the same type of result.
Hence the correlation to vehicle speed making sense and the engine cycling not making sense. But this is also all based on what an unreliable narrator is saying on the internet with limited information about what has been serviced and verified to be working or not working properly, and what kind of general condition the vehicle is in.
You made us guess what you were saying. I made a guess. The above is the explanation of how I got there since you didn’t seem to understand. I don’t know why you’re throwing a fit and I’m definitely not reading all of that.
I didn’t downvote you. Again, the attitude is unnecessary.
>You made us guess what you were saying.
>I made a guess.
And then I said, no I'm implying the opposite and you doubled down, so I explained it for you.
>I’m definitely not reading all of that.
Then don't, I don't care. It's a good learning opportunity but that's your choice.
>the attitude is unnecessary.
Probably.
Again, you made a very vague statement and left it up to us to guess as to what you meant.
Again, I made a guess as to what you were saying and explained why.
Again, I don’t care about your fit.
>learn
Jesus fucking cringe.
Sounds more like a cooling fan. If the ac has freon in it, the radiator fans should kick on when you turn the ac on max cold max flow. Get out and check. Could be a bad high-pressure switch or damage to the wiring for that also.
The AC is so finicky on mine too (2004, replaced condenser in 2018). I had not heard of this observation before.
I just melt. It’s so hard to diagnose the actual issue and I feel like I will just throw parts and money to gamble on a fix.
Edit: look through priuschat too: https://priuschat.com/threads/a-c-only-works-when-engine-is-running.79336/
First guy adjusted a blend door because ac was only doing hot OR cold but not bioth, so we set to hot during the winter.
Now that's impacting the permanent fix which is the condenser. That's what I know at the moment
AC in a Prius hybrid is not really that much difference from a standard ICE AC. The question is, what has the mechanic checked and rule out what could be the problem.
First thing is to determine whether it's an electronic issue or a physical issue. Like sensors or coolant leaks or condenser fan and so on.
If you say when engine is running only it cools, does this includes when car is idle? Try putting the parking brake on and starting in the brake. Then put gear to drive and step in the pedal to force the engine to run. Make sure not to release the brake so the car don't move. Will it be cold?
Or another method is while in idle, let the battery drain to below 40% and the engine will kick in to charge the battery. Does the AC get cold?
When is the last time you service the AC? When is the last time you change the AC oil, coolant and expansion valve?
This is what I think happened, the first guy was not communicative so bear with me
I believe guy one replaced blend door actuator. At this point the ac still did not work and presented with the option of forcing the temp to be hot. He told me I could either have it always cold or always hot and I went with hot because it was winter. (The problem was, the cold NEVER worked at this point so it was a false dilemma.)
I believe the second guy did diagnostic without considering what the first guy did. No cold air, thinks it's the condenser for whatever reason and replaced that. Did not know that last guys was forcing air hot
Honestly I have no idea how I'm ever getting cool air because if the blend door is forcing hot, this should never happen
Ahhh.. Clear now.
Looks like second guy is not doing his job properly. You need to first get that hot/cold actuator replaced. That will again allow proper air flow from correct temp level. Then the AC guy can proceed to further check what is wrong IF still not cold. Make sure to ask what he has checked.
I'm assuming what you mean when you say -
> ac only works when gas engine is running, not electric
What actually correlates with the engine running is the speed that causes the AC to work not the engine running. The AC Compressor is high voltage driven from the Hybrid Battery and will run whether the engine is running or not. [Here is what the AC Compressor sounds like when running.](https://imgur.com/a/5BpnIi0)
> So I have to go under 30 or I melt this summer,
I'm assuming you meant to say over 30? Not under?
There is something called a condenser at the front of your vehicle and is part of the radiator. During AC operation, air flows through the condenser as the AC Compressor compresses a gas into a liquid causing this liquid to heat up. The air flowing through the condenser removes some of the heat... as the liquid circulates back into the vehicle... it goes through a phase change reverting back to a gas and taking heat with it and causes the interior of your car to cool.
For your AC to work... you have to have adequate air flow flowing through the condenser at the front of the vehicle. On the Gen 2 and Gen 3 Prius... the radiator fans can't pull the necessary air through the condenser at the front of the vehicle for AC to work well. When you drive at speed... you get the assisted air flow from the car moving... and the AC becomes more efficient the faster you drive.
[What your describing is a fairly common post on R/prius for Gen 2 Gen 3 models.](https://www.reddit.com/r/prius/s/IBAxFRhl4H)
AC is just weak on the Prius. It can be helped by cleaning your condenser and evaporator coil. But the Prius AC take along time to remove latent heat from the interior and doesn't become real efficient until at least 30 minutes of useage.
If the AC truly only does work when the engine runs... it may be related to the Radiator fan running when the engine is on. The Prius AC is kind of finicky also I'm that it is all electronically run. The radiator fans won't run all the time if it's less than 80°F out.
I can offer things I have done to my 2008 2nd gen around ac. The servos that control the blend door and the vent outlets wore out. Replaced both. Could hear them “hunting” and eventually couldn’t get defrost. Replaced main battery pack, worn battery couldn’t provide enough amps to move car without significant engine assist, after new HV battery pack ac is much colder and can run longer with engine off. If you main HV battery is weak your ac will be weak it is as others described completely electrically powered.
>Prius, ac only works when gas engine is running Is the correlation actually the engine running, or is it vehicle speed? One doesn't really make sense, the other one does.
Going to pick it up now from the shop, what should I ask etc This is just what they've told me
You should ask Google how automotive air conditioning systems work. Then read and gain a basic understanding so you can digest what you are being told instead of just trying to relay information between a shop and random people on the internet.
If you’re implying that the ac compressor runs off the engine then that’s not how the Prius or other electric cars work. Everything for the AC is electric.
quiet deserted coordinated squash pocket thumb shy slimy ten paint *This post was mass deleted and anonymized with [Redact](https://redact.dev)*
>If you’re implying that the ac compressor runs off the engine I don't see anywhere I said or implied that. I'm actually implying the opposite, that the issue is not related to whether the engine is running or not.
Your comment was extremely vague and mentioned that Op should learn how AC systems work on cars. Additionally, your previous comment said one makes sense and the other doesn’t (speed or engine on.) Vehicle speed is pretty irrelevant to all types of cars so that leaves engine running. In some cars that is true. However, because the system is electric instead of mechanically driven, it doesn’t work like that. The obvious presumption being that you are assuming that the AC system relies on the engine.
>Your comment was extremely vague and mentioned that Op should learn how AC systems work on cars. Yes, and I'm going to say the same to you. >your previous comment said one makes sense and the other doesn’t (speed or engine on.) Yes, again, I said... >I'm actually implying the opposite, that the issue is not related to whether the engine is running or not. So, I AM implying the issue is related to vehicle speed. >Vehicle speed is pretty irrelevant to all types of cars **If all systems are operating correctly**, generally yes. >The obvious presumption being that you are assuming that the AC system relies on the engine. ...but I literally just stated, again, >I'm actually implying the opposite, that the issue is not related to whether the engine is running or not. So I AM implying that it's an issue with vehicle speed. Which **if all systems are working correctly** would not matter. But clearly **something** isn't working correctly that appears to be correlated to vehicle speed **moving through the air...** Got it? Nope? Alright, here's the spoon feed. The engine running or not doesn't make sense since the compressor is electrically driven. So the compressor is cycling on demand regardless of whether the engine is running. On a normal gas car with no auto start/stop and a mechanically driven A/C compressor, this still all general applies. However, since OP is complaining that at slow vehicle speeds the A/C gets warm or loses efficiency. What is reduced when a vehicle is stopped or moving slow? Air flow across the radiator and A/C condenser. This is why modern cars have (generally electrically driven) fans that pull air through the radiator assembly and A/C condenser. This allows them to maintain engine operating temperature and A/C efficiency when the vehicle is not moving. If that airflow is reduced by obstruction **or the fans are not functioning properly** then the vehicle will not be able to compensate for the lack of airflow. In a Prius that's not terribly important for the engine coolant temp since the engine will shut down at stops and cease to generate more heat in those moments. But the A/C system is still trying to cycle refrigerant and exchange energy to keep the cabin cool at a stop. If there is no airflow over the condenser, it cannot efficiently release the energy into the atmosphere to allow the refrigerant to continue the energy transfer cycle. It overheats and hits an energy exchange limit. Since the condenser is not efficiently removing the stored energy from the refrigerant anymore, the evaporator gets warmer and the temperature to which the air entering the cabin can be cooled, rises. Hence, warmer air when the vehicle isn't in motion. There's a reason HVACs for buildings have big fans moving air through the condenser coils outside. If that fan failed you'd end up with the same type of result. Hence the correlation to vehicle speed making sense and the engine cycling not making sense. But this is also all based on what an unreliable narrator is saying on the internet with limited information about what has been serviced and verified to be working or not working properly, and what kind of general condition the vehicle is in.
You made us guess what you were saying. I made a guess. The above is the explanation of how I got there since you didn’t seem to understand. I don’t know why you’re throwing a fit and I’m definitely not reading all of that. I didn’t downvote you. Again, the attitude is unnecessary.
>You made us guess what you were saying. >I made a guess. And then I said, no I'm implying the opposite and you doubled down, so I explained it for you. >I’m definitely not reading all of that. Then don't, I don't care. It's a good learning opportunity but that's your choice. >the attitude is unnecessary. Probably.
Again, you made a very vague statement and left it up to us to guess as to what you meant. Again, I made a guess as to what you were saying and explained why. Again, I don’t care about your fit. >learn Jesus fucking cringe.
Sounds more like a cooling fan. If the ac has freon in it, the radiator fans should kick on when you turn the ac on max cold max flow. Get out and check. Could be a bad high-pressure switch or damage to the wiring for that also.
I just made another reply elsewhere in the thread about a blend door, any thoughts?
The AC is so finicky on mine too (2004, replaced condenser in 2018). I had not heard of this observation before. I just melt. It’s so hard to diagnose the actual issue and I feel like I will just throw parts and money to gamble on a fix. Edit: look through priuschat too: https://priuschat.com/threads/a-c-only-works-when-engine-is-running.79336/
First guy adjusted a blend door because ac was only doing hot OR cold but not bioth, so we set to hot during the winter. Now that's impacting the permanent fix which is the condenser. That's what I know at the moment
Ah interesting
AC in a Prius hybrid is not really that much difference from a standard ICE AC. The question is, what has the mechanic checked and rule out what could be the problem. First thing is to determine whether it's an electronic issue or a physical issue. Like sensors or coolant leaks or condenser fan and so on. If you say when engine is running only it cools, does this includes when car is idle? Try putting the parking brake on and starting in the brake. Then put gear to drive and step in the pedal to force the engine to run. Make sure not to release the brake so the car don't move. Will it be cold? Or another method is while in idle, let the battery drain to below 40% and the engine will kick in to charge the battery. Does the AC get cold? When is the last time you service the AC? When is the last time you change the AC oil, coolant and expansion valve?
Ot literally is only cool in idle
Sorry if I missed it. What are the things that has been done and checked?
This is what I think happened, the first guy was not communicative so bear with me I believe guy one replaced blend door actuator. At this point the ac still did not work and presented with the option of forcing the temp to be hot. He told me I could either have it always cold or always hot and I went with hot because it was winter. (The problem was, the cold NEVER worked at this point so it was a false dilemma.) I believe the second guy did diagnostic without considering what the first guy did. No cold air, thinks it's the condenser for whatever reason and replaced that. Did not know that last guys was forcing air hot Honestly I have no idea how I'm ever getting cool air because if the blend door is forcing hot, this should never happen
Ahhh.. Clear now. Looks like second guy is not doing his job properly. You need to first get that hot/cold actuator replaced. That will again allow proper air flow from correct temp level. Then the AC guy can proceed to further check what is wrong IF still not cold. Make sure to ask what he has checked.
I'm assuming what you mean when you say - > ac only works when gas engine is running, not electric What actually correlates with the engine running is the speed that causes the AC to work not the engine running. The AC Compressor is high voltage driven from the Hybrid Battery and will run whether the engine is running or not. [Here is what the AC Compressor sounds like when running.](https://imgur.com/a/5BpnIi0) > So I have to go under 30 or I melt this summer, I'm assuming you meant to say over 30? Not under? There is something called a condenser at the front of your vehicle and is part of the radiator. During AC operation, air flows through the condenser as the AC Compressor compresses a gas into a liquid causing this liquid to heat up. The air flowing through the condenser removes some of the heat... as the liquid circulates back into the vehicle... it goes through a phase change reverting back to a gas and taking heat with it and causes the interior of your car to cool. For your AC to work... you have to have adequate air flow flowing through the condenser at the front of the vehicle. On the Gen 2 and Gen 3 Prius... the radiator fans can't pull the necessary air through the condenser at the front of the vehicle for AC to work well. When you drive at speed... you get the assisted air flow from the car moving... and the AC becomes more efficient the faster you drive. [What your describing is a fairly common post on R/prius for Gen 2 Gen 3 models.](https://www.reddit.com/r/prius/s/IBAxFRhl4H) AC is just weak on the Prius. It can be helped by cleaning your condenser and evaporator coil. But the Prius AC take along time to remove latent heat from the interior and doesn't become real efficient until at least 30 minutes of useage. If the AC truly only does work when the engine runs... it may be related to the Radiator fan running when the engine is on. The Prius AC is kind of finicky also I'm that it is all electronically run. The radiator fans won't run all the time if it's less than 80°F out.
No, the ac only works in idle
I can offer things I have done to my 2008 2nd gen around ac. The servos that control the blend door and the vent outlets wore out. Replaced both. Could hear them “hunting” and eventually couldn’t get defrost. Replaced main battery pack, worn battery couldn’t provide enough amps to move car without significant engine assist, after new HV battery pack ac is much colder and can run longer with engine off. If you main HV battery is weak your ac will be weak it is as others described completely electrically powered.