A/C recirc in manual, but not Auto

[Ruralmoondog1]

Good day,

I have a 2016 5.7L that came factory with the single zone, 7spd non-auto system.

I purchased the single zone auto temp retrofit kit from M2Mods4Ram and the recirc worked when installed.

Starting a bit ago, I can’t turn recirculation on while it is set to AUTO. In manual control, I can.

Any ideas on where to start? I replaced the humidity sensor with an Amazon special one and that didn’t fix it.

 

[carlylelocke]

I had to use a genuine Mopar/Chrysler part from a real FCA parts store online, fixed my blinking recirc button and code it was throwing (both amazon and AutoZone off brand did not work). but it still blinks sometimes when the cab is warm and humid. I have had a multitude of problems with HVAC in my 2017, will be leaving the RAM family later this year.

 

[Dean2]

Assuming you don't have a defective part, the AC system is designed to disallow recirculate on auto when the air condition inside the cab is wrong. If you push recirc when disallowed, the light will blink. Too high a humidity is one of those. You also see it in winter, it won't engage recirc on defrost at all in auto or on regular heat if the air is too damp. Helps keep your windows from frosting on the inside. All the heavily frosted windows we see in winter are immigrants who don't know they need to use outside air in cold weather. They think recirc will help heat the car faster, so they use that and end up with a quarter inch of ice on the inside of the windows..

 

[carlylelocke]

Assuming you don't have a defective part, the AC system is designed to disallow recirculate on auto when the air condition inside the cab is wrong. If you push recirc when disallowed, the light will blink. Too high a humidity is one of those. You also see it in winter, it won't engage recirc on defrost at all in auto or on regular heat if the air is too damp. Helps keep your windows from frosting on the inside. All the heavily frosted windows we see in winter are immigrants who don't know they need to use outside air in cold weather. They think recirc will help heat the car faster, so they use that and end up with a quarter inch of ice on the inside of the windows..

Good to know. I'm in Houston so it's very frequent. Wish that was the only issue. Fan motor and blender door seem to do their own thing when the cab is hot too. I use manual controls every day now, which is sad cause I used auto ac a lot for convenience. Again though, thanks.

 

[HarryS]

If you use anything besides a genuine Mopar humidity sensor, it won't work. I've tried the dorman, and it failed. I tried a used Mopar, and it failed, only a brand new mopar sensor fixed my issue.

 

[Ruralmoondog1]

Assuming you don't have a defective part, the AC system is designed to disallow recirculate on auto when the air condition inside the cab is wrong. If you push recirc when disallowed, the light will blink. Too high a humidity is one of those. You also see it in winter, it won't engage recirc on defrost at all in auto or on regular heat if the air is too damp. Helps keep your windows from frosting on the inside. All the heavily frosted windows we see in winter are immigrants who don't know they need to use outside air in cold weather. They think recirc will help heat the car faster, so they use that and end up with a quarter inch of ice on the inside of the windows..

Didn’t know this, thank you. Will test today and if the cabin is less humid, I’ll replace the sensor.

 

[crash68]

@Ruralmoondog1 the auto control of air temperature still works even if the Auto light is not on. When the light isn't on it's the fan speed, AC enable, and mode dampers that are effected.