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.
5thgenrams.com
