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A/C Performance

@Jhill, thanks, but I there are several pitfalls with that approach. I posted related info in another thread:


Besides, the plastic vent louvers that the IR reads will always be a little warmer than the vent air that is cooling them, so the IR must always read at least as warm as my probe thanks to science. Nevertheless, tomorrow I will use an industrial IR gun from our plant to demonstrate the comparison for the dealer.
 
Has anyone actually reported they get consistent vent temps on both vents in the 40's without modifying anything?
There's a few posters on the following thread that say their A/C is good.
AC - does anyone have a truck that blows ice cold?
 
There's a few posters on the following thread that say their A/C is good.
AC - does anyone have a truck that blows ice cold?

Thanks, I am looking for actual vent temp readings on both sides for folks who say it's "ice cold"
 
Not so fast. My new 2019 2500 build date was 4/19/2019. Took it into the dealer with 63°F on the driver's center vent, and 55°F on the passenger vent on an 81°F day. The service rep hadn't heard of this problem yet, but that can't be possible. After confirming good high/low refrig pressures, they "recalibrated" the blend doors. I have no idea what that really means, calibration is not the right word. Anyway, now I get 62°F driver and 54°F passenger on the center console with 93°F ambient. Better, but that 62°F was after 20 minutes of cooldown with RPMs at 1500.

The service rep used an IR gun and called the driver's vent 43°F. If anything needs to be recalibrated, it is the service tech's IR thermometer! I validated calibration on my probe by ensuring that it read the same air temperature as the RAM, and then checked if it read freezing in icewater. (It read 34°F in the equilibrium ice bath.) So, for my thermometer, the calibration "zero" is -2°F, and the calibration "span" is 1.043 °/°, which basically means the calibration is valid for thermometer accuracy to within 2 F° between 32°F - 81°F.

So, now I have two problems: my A/C is working unacceptably poorly on my brand new HD RAM, and the dealer techs do not have the tools to properly diagnose the issue. I suppose I could ask to witness the temperature reading at the dealer...

EDIT: It is possible that the dealer IR gun read a cold temperature, and then as soon as the engine was shut off, the blend door "calibration" reverted back to the misaligned setting. Could be why my temps are back up. I will give the dealer the benefit of the doubt.
Sorry to hear this, Maestro. Sounds like it’s still hit or miss with the AC in the new gen Rams.
 
My truck was recently built 5/14/19. Just ran a little test today and got lowest vent temps of 51.8 from the driver/center vent, 43.9 from the passenger/center. It would appear they haven’t implemented an across-the-board fix on the assembly line.

Conditions:
No heater hose clamp or valve
Engine up to normal operating temp
Driving on highway 65 mph
Ambient temp 78
Fan HI
Driver/passenger temps set to LO
Recirculate ON
 
Not sure what you definition of ICE COLD is, but I consider 40 degree vent temps pretty good. I don't want my arms or cheeks getting numb....

There's a few posters on the following thread that say their A/C is good.
AC - does anyone have a truck that blows ice cold?
 
Here are pics of the temp coming out of my vent today, with it 82 out, I have an appointment with a different dealership than I usually go to because they seemed to think this was working as designed. The dealership tech decides to make up his own test procedure by placing his hand over the vent and says it was cool enough for him.
 

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I just received a response from Andre Smirnov from TFLtrucks from an email I sent them asking if they had noticed poor AC performance on their Rebel long term truck, including info about the up to 8 degree warmer temps from drivers center vent. He says that they have not noticed this as it has not been very hot yet, but they would look into it in coming weeks.
It looks like they actually started to look into this....

 
A little info I’ve discovered. My A/C has always been sub par since I’ve got my truck. I have recently had my engine software updated. The first time I noticed right away my cooling fan for the engine is running a lot faster speed. I also have noticed the A/C has been a lot better. I have had it running all year the hottest being about 90 degrees but it is obviously better.

I have since had the HVAC update and checked again for all updates, then there was another engine or PCM update linking to a bulletin for cooling fan issues, improved cooling and fan operation. I was hesitant to get that updated because the A/C has been better than ever. I had it done. Good news is it didn’t slow my engine fan down when’re ore starting when hot that is where I first noticed the difference from the first PCM update done in the winter. Previously if remote started the truck the radiator fan was running but not very fast. Now it is moving some air across the condenser. It’s obvious mine is an earlier build but theY haven’t had enough airflow to cool the condenser making the A/C struggle to cool the truck. Not now. If I drop the temp down and leave it on auto from say 69 to 64 you can hear the radiator fan ramp up, turn it back up the fan slows down. Also when driving after sitting the fan stays quite high but the A/C works much better after a few mikes on the drive home the fan will slow down with the temp set the same as it was when first starting. I have actually had to turn the A/C down on my 20-30 minute drive home after work The truck is heat was heat soaked. The highest ambient temp after sitting was 96 when first started then settled to 86 by the time I was home. So not mid to upper 90’a yet but it is a lot better than ever.

The reason there is no shut off valve is because of the dual zone heater box they would need a compete redesign for that to be the way to fix the issue. You would need two cores two valves etc. not going to happen. The hack works for two reasons, you don’t have a 190 plus degree heat soaked heater core inside the box so the overall temp is going to lower and two if there is any bleed through the blend door it obviously isn’t going to be a factor now being there is no heat in the heater core. I’ve had the doors calibrated,didn’t do anything.

The reason I believe the drivers side is warmer than the passenger is because the evaporator isn’t really cold enough to begin with. On a dual zone system if the refrigerant is low say 5 ounces in a 16 ounce system the passenger side feels ok the drivers is not, it’s warm. Charge it up and they both are cold. I’ve seen it a lot on Honda’s that I work on. The condenser needs to remove heat which lowers pressures in the system and provides cooler air, the fan is where that comes from. I have no idea if the shutters were closed or open etc but the fan is moving a lot more air across the condenser resulting in lower vent temps. You will hear the fan while driving more now but as you speed up is slows down, come to a stop after a few minutes sitting it will ramp up.

No I have not checked the vent temps like I did last year where there was up to 8 degrees difference , but my hand tells me it’s much more equal. My truck cools down now. You do need to use recirc or it won’t really get cold like it does on recirc. Never will. I suspect maybe a 2-3 temp difference but preciously you could feel,it with your hands. You will always get a warmer temp the further away from the evaporator you go, 8 degrees was too much.

If you have your truck In for A/C poor performance have them update your PCM it will link to a bulletin describing the issue, none of which say anything about A/C performance. It will make a difference. Also, if you fan is pretty loud already when you remote start after sitting, this may not be your issue. It was. Mine. If your fan doesn’t ramp up and down while driving in the heat or switching vent temps from 70 to 63 on auto this may not help. If you leave it on max A/C the internal blower fan will be at a lower speed than if you set the temp to Lo and use Auto. So use Auto. To see if your radiator fan changes with temp setting changes. The AUTO setting blows like crazy, the higher the blower speed inside the truck the warmer the air coming out of the vents will be. it’s all about heat dissipation. Slower blower speed iequal cooler temps but lacks airflow. Max A/C works good too, just different.

The recirc function on auto appears to have been changed, I seem to have to select it now where previously it would be on recirc, but the light wasn’t on. You can hear the cab being louder because the air is getting sucked from behind the glove box, switch to fresh, it gets quieter. The have always had a mind of its own, sometimes even would switch on its own even not on auto. My 4th gen would do that too if the temp couldn’t be reached when in manual mode.

This is with the current HVAC software update done that was previously not applicable to mine and a lot of trucks. Ram Cares provided info stating there was an error and some configurations were left out. Mine popped up as needing it now where a few months ago it didn’t. This may need to be done to get the same results I have had since it might have some effect on the radiator fan speed as well. It’s obvious Ram is tweaking this to help. I think the bulletin for the radiator fan is pretty recent, so most or all trucks on the road now aren’t going to have it.

My truck is granite metallic I have the windows and pano roof ceramic tinted since I got it last year when I could not stand the heat, so if yours isn’t, your results may vary, but it should improve your A/C from what it was.

Is it an Ice cold A/C ? No, I’ve never seen one yet since the old R12 stuff from the 70’s and 80’s but it is much improved and appears to be acceptable to me for this day and age. Ive worked on a lot of cars and get in them daily.

Sorry for the long post
Hopefully this will help some people.
 
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A little info I’ve discovered. My A/C has always been sub par since I’ve got my truck. I have recently had my engine software updated. The first time I noticed right away my cooling fan for the engine is running a lot faster speed. I also have noticed the A/C has been a lot better. I have had it running all year the hottest being about 90 degrees but it is obviously better.

I have since had the HVAC update and checked again for all updates, then there was another engine or PCM update linking to a bulletin for cooling fan issues, improved cooling and fan operation. I was hesitant to get that updated because the A/C has been better than ever. I had it done. Good news is it didn’t slow my engine fan down when’re ore starting when hot that is where I first noticed the difference from the first PCM update done in the winter. Previously if remote started the truck the radiator fan was running but not very fast. Now it is moving some air across the condenser. It’s obvious mine is an earlier build but theY haven’t had enough airflow to cool the condenser making the A/C struggle to cool the truck. Not now. If I drop the temp down and leave it on auto from say 69 to 64 you can hear the radiator fan ramp up, turn it back up the fan slows down. Also when driving after sitting the fan stays quite high but the A/C works much better after a few mikes on the drive home the fan will slow down with the temp set the same as it was when first starting. I have actually had to turn the A/C down on my 20-30 minute drive home after the truck is heat soaked. The highest ambient temp after sitting was 96 when first started then settled to 86 by the time I was home. So not mid to upper 90’a yet but it is a lot better than ever.

The reason there is no shut off valve is because of the dual zone heater box they would need a compete redesign for that to be the way to fix the issue. You would need two cores two valves etc. not going to happen. The hack works for two reasons, you don’t have a 190 plus degree heat soaked heater core inside the box so the overall temp is going to lower and two if there is any bleed through the blend door it obviously isn’t going to be a factor now being there is no heat in the heater core. I’ve had the doors calibrated,didn’t do anything.

The reason I believe the drivers side is warmer than the passenger is because the evaporator isn’t really cold enough to begin with. On a dual zone system if the refrigerant is low say 5 ounces in a 16 ounce system the passenger side feels ok the drivers is not, it’s warm. Charge it up and they both are cold. I’ve seen it a lot on Honda’s that I work on. The condenser needs to remove heat which lowers pressures in the system and provides cooler air, the fan is where that comes from. I have no idea if the shutters were closed or open etc but the fan is moving a lot more air across the condenser resulting in lower vent temps. You will hear the fan while driving more now but as you speed up is slows down, come to a stop after a few minutes sitting it will ramp up.

No I have not checked the vent temps like I did last year where there was up to 8 degrees difference , but my hand tells me it’s much more equal. My truck cools down now. You do need to use recirc or it won’t really get cold like it does on recirc. Never will. I suspect maybe a 2-3 temp difference but preciously you could feel,it with your hands. You will always get a warmer temp the further away from the evaporator you go, 8 degrees was too much.

If you have your truck In for A/C poor performance have them update your PCM it will link to a bulletin describing the issue, none of which say anything about A/C performance. It will make a difference. Also, if you fan is pretty loud already when you remote start after sitting, this may not be your issue. It was. Mine. If your fan doesn’t ramp up and down while driving in the heat or switching vent temps from 70 to 63 on auto this may not help. If you leave it on max A/C the internal blower fan will be at a lower speed than if you set the temp to Lo and use Auto. So use Auto. The AUTO setting blows like crazy, the higher the blower speed inside the truck the warmer the air coming out of the vents will be. it’s all about heat dissipation. Slower blower speed iequal cooler temps but lacks airflow.

This is with the current HVAC software update done that was previously not applicable to mine and a lot of trucks. Ram Cares provided info stating there was an error and some configurations were left out. Mine popped up as needing it now where a few months ago it didn’t. This may need to be done to get the same results I have had since it might have some effect on the radiator fan speed as well. It’s obvious Ram is tweaking this the help. I think the bulletin for the radiator fan is pretty recent, so most or all trucks on the road now aren’t going to have it.

My truck is granite metallic I have the windows and pano roof ceramic tinted since I got it last year when I could stand the heat, so if yours isn’t, your results may vary, but it should improve your A/C for what it was.

Is it an Ice cold A/C ? No, I’ve never seen one yet since the old R12 stuff from the 70’s and 80’s but it is much improved and appears to be acceptable to me for this day and age. Ive worked on a lot of cars and get in them daily.

Sorry for the long post
Hopefully this will help some people.
Do you happen to know the TSB for the software update on the PCM?
 
No I don’t. I didn’t write it down, I worked for Chrysler 20 years ago and still,have friends at the dealership if you know what I mean. When they hook your truck up the module tree shows all modules that have an update available. Once they click on them it pops open a TSB describing the issues and improvements. I don’t know why some dealers are so reluctant to help people out. Software updates are simple. It’s a fairly quick update. The driving assistance lane departure etc took over an hour though. Not related. Just had. Everything updated.
 
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I made a similar comment a few months back - after taking my truck in for my 2nd service and fighting with the service adviser about some TSBs (none A/C related) I noticed that my A/C was marginally better and I noticed my electric cooling fans seemed to be running on high MUCH more this summer than last summer. I thought it was in my head but nice to see someone else confirm. I can definitely hear the engine fans at full blast when I'm riding around town, which is not something I remember from my first 4 months of ownership.

However, the difference is a minor improvement at best - the A/C is still sub-par compared to any other vehicle I've driven this year. I'll be asking them to perform the A/C TSB when I go in for my next oil change in a few weeks.
 
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I didn't get to watch the whole video, anyone care to share the results? (the numbers, not the opinions) I'm in a spot now where I can't use sound at the moment...

I'll say this, at the risk of being flamed, one truck performing better than the other does not constitute a problem.
 
The Ram was blowing 52 when the Ford was 42 The Ford won but it was closer than I thought it would be. But 42 degree blowing on you feels a lot better than 52 but overall cab cool down time wasn’t too far off. I think the ford hit 70 and the Ram was at under 73.
 
The Ram was blowing 52 when the Ford was 42 The Ford won but it wasn’t as bad as I thought it was going to be.

Thanks, what about the ambient temps over time? Vent temp means nothing, the air can come out of the vents at whatever temp it wants, if there's more volume in one truck vs the other, the trucks could cool at the same rate. Did they both get to 70 (center thermometer) at the same time?
 
No the ford hit 70 first when the Ram was like 72.5 or something, just going off memory. They closed the sunshade and the ford cooled down quicker than the Ram with the sunshade closed.

I was waiting for the Ford ice box that I keep hearing about. Didn’t see it.

The Ram pano is HOT, I tinted mine and windows with ceramic. Much improved
 
Quite the victory...

Thanks again for relaying the info to me
The other difference which goes a long way in regards to the temperature feel is that there was a 8% difference in relative humidity in the trucks 32% for the Ford and 40% for the RAM.
 
Not so fast. My new 2019 2500 build date was 4/19/2019. Took it into the dealer with 63°F on the driver's center vent, and 55°F on the passenger vent on an 81°F day. The service rep hadn't heard of this problem yet, but that can't be possible. After confirming good high/low refrig pressures, they "recalibrated" the blend doors. I have no idea what that really means, calibration is not the right word. Anyway, now I get 62°F driver and 54°F passenger on the center console with 93°F ambient. Better, but that 62°F was after 20 minutes of cooldown with RPMs at 1500.

The service rep used an IR gun and called the driver's vent 43°F. If anything needs to be recalibrated, it is the service tech's IR thermometer! I validated calibration on my probe by ensuring that it read the same air temperature as the RAM, and then checked if it read freezing in icewater. (It read 34°F in the equilibrium ice bath.) So, for my thermometer, the calibration "zero" is -2°F, and the calibration "span" is 1.043 °/°, which basically means the calibration is valid for thermometer accuracy to within 2 F° between 32°F - 81°F.

So, now I have two problems: my A/C is working unacceptably poorly on my brand new HD RAM, and the dealer techs do not have the tools to properly diagnose the issue. I suppose I could ask to witness the temperature reading at the dealer...

EDIT: It is possible that the dealer IR gun read a cold temperature, and then as soon as the engine was shut off, the blend door "calibration" reverted back to the misaligned setting. Could be why my temps are back up. I will give the dealer the benefit of the doubt.
I had the same issue with my dealership and using an infared gun is against RAM's own test procedures which specifically stated to insert a thermometer into the vent. When I went to a different dealership after getting RAM customer service involved it was determined mine was low on refrigerant. I would definitely get RAM involved because your dealership is making up their own test procedures.
 
The other difference which goes a long way in regards to the temperature feel is that there was a 8% difference in relative humidity in the trucks 32% for the Ford and 40% for the RAM.
I don't have a horse in this race, because I am satisfied that my
A/C is preforming to factory specs and makes me comfortable even when temps are in the high 90's, but in the case of the test, even though the relative humidity was different in each vehicle, what you should focus on is the thermometer readings.
 

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