2015 Jeep Wrangler Engine Fan and AC Compressor Run When It's Raining

[brianl703]

Way back I remember seeing lots of cars with fogged up windows from the inside during rainy days it was quite common, not anymore.

It's that hard for the average driver to figure out that turning on the defroster fixes that???

 

[dogememe]

You can hear the ac compressor cycling when sitting at a stop light, and the fan wind down as soon as you shut off the ignition. Most people that have any mechanical aptitude would notice it.

It sounds silly but it would bother me too. Pointless extra load wasting gas and power.

 

[Thermo1223]

It's that hard for the average driver to figure out that turning on the defroster fixes that???

Yes...because it's also hard for them to use headlights at dusk, or when foggy so other cars can see them. It is also extremely hard for them to replace a light bulb instead of just using high beams in the city. It's also hard for them to use headlights when it is also raining. All of these things increase safety but they are very hard for the average driver.

 

[dogememe]

Yes...because it's also hard for them to use headlights at dusk, or when foggy so other cars can see them. It is also extremely hard for them to replace a light bulb instead of just using high beams in the city. It's also hard for them to use headlights when it is also raining. All of these things increase safety but they are very hard for the average driver.

Well half of people are dumber than average

 

[brianl703]

Yes...because it's also hard for them to use headlights at dusk, or when foggy so other cars can see them. It is also extremely hard for them to replace a light bulb instead of just using high beams in the city. It's also hard for them to use headlights when it is also raining. All of these things increase safety but they are very hard for the average driver.

Sounds like Idiocracy wasn't fiction, it was a documentary.

 

[explorer2030]

I'm not bothered by it with confirmation that it's normal behavior and not a malfunction. It concerned me because the only related statement in the owners manual says that the compressor only runs in mix, defrost, or a blend of these modes without the AC button pressed. There is no mention in the 2015 Jeep manual that the fan or the compressor will run based on windshield wiper usage as mentioned in that 2001 Chrysler Minivan TSB when it's not in mix or defrost modes with the AC button off.

 

[D60]

My JL triggers the headlamps with wipers. I think I can turn it off in the myriad menus.

As a non-traditional driver who wants control over everything, it drives me nuts. Plus here in CO light sprinkles are considered heavy rain, and it may be sunny and "raining". It dims the instrument cluster and then I'm annoyed by not being able to see my gauges on those sunny, rainy days

 

[Thermo1223]

Sounds like Idiocracy wasn't fiction, it was a documentary.

Driving through my town yesterday, I could hear the great voice of Cronkite or Freeman in my head narrating the idiocy a foot.

 

[explorer2030]

Today I decided to do some further testing with wiper usage when it was dry and not raining. I started the vehicle and drove about 10 miles with the blower on regular vent, ac off and defrost off, and I found that the AC compressor and the fan were off as expected. From this point I continued on for about another 15 miles with the same blower settings, except I turned on the wipers and found that the AC compressor and the fan then turned on.

With the vehicle still running, I pressed the AC button on and off which shut down the AC compressor but not the fan. I then continued driving for about 15 more miles with the same blower settings and the wipers on, but found that the AC compressor never came back on. It seems that if the AC compressor is turned on initially by the use of the wipers during a drive cycle, and then turned off by someone manually pressing the AC button on and off, it never turns back on with continued wiper usage until the vehicle is shut down and restarted.

Any ideas on logic behind this? I would think that you wouldn't want to totally kill the dehumidifying process with the AC compressor for the entire drive cycle if someone accidentally hits the AC or the Recirculate button.

 

[KrisZ]

Today I decided to do some further testing with wiper usage when it was dry and not raining. I started the vehicle and drove about 10 miles with the blower on regular vent, ac off and defrost off, and I found that the AC compressor and the fan were off as expected. From this point I continued on for about another 15 miles with the same blower settings, except I turned on the wipers and found that the AC compressor and the fan then turned on.

With the vehicle still running, I pressed the AC button on and off which shut down the AC compressor but not the fan. I then continued driving for about 15 more miles with the same blower settings and the wipers on, but found that the AC compressor never came back on. It seems that if the AC compressor is turned on initially by the use of the wipers during a drive cycle, and then turned off by someone manually pressing the AC button on and off, it never turns back on with continued wiper usage until the vehicle is shut down and restarted.

Any ideas on logic behind this? I would think that you wouldn't want to totally kill the dehumidifying process with the AC compressor for the entire drive cycle if someone accidentally hits the AC or the Recirculate button.

You can only nanny things so much, I guess the logic is that if a user hit the ac button to turn it on and then hit it again to turn it off, he/she wants it off, because maybe they are cold.

At the end of the day, you have to give the user some control because you cannot account for all possible scenarios, that is why even fully automatic climate controls allow for manual override of settings.

In my minivan I leave the climate control on auto and just adjust the temperature, however I had some situations where I needed to manually adjust vent settings, because the system didn’t get it right. But that’s rare, overall the system gets the job done and keeps the cabin comfortable all by itself.

 

[demarpaint]

You can hear the ac compressor cycling when sitting at a stop light, and the fan wind down as soon as you shut off the ignition. Most people that have any mechanical aptitude would notice it.

You're giving too many people credit for mechanical aptitude. All kidding aside, I found most people have little to no mechanical aptitude.

 

[D60]

You're giving too many people credit for mechanical aptitude. All kidding aside, I found most people have little to no mechanical aptitude.

My wife literally doesn't notice when the ESS is working in our JL. I panic and wonder why the vehicle shut down but 99% of drivers have no clue

 

[demarpaint]

My wife literally doesn't notice when the ESS is working in our JL. I panic and wonder why the vehicle shut down but 99% of drivers have no clue

I was a passenger in a 2022 MB SUV with ESS a few weeks ago. Every time it restarted the vehicle jerked so much so that my wife noticed it. I wonder if Jeep has it down better than MB?

 

[ElectroMechanoMan]

Most vehicles I owned turn on AC any time defrost is on. I’d have to test to see if my vehicles operate as yours does. The ESS on my Fords actually works quite well. I temporarily disable it after coming off of a “hard” drive such as trailer towing with the truck or high speed freeway driving so the turbochargers have a chance to cool off. The start is very smooth and almost undetectable if it wasn’t for the starter sound.

 

[dumkid]

do people not know to turn on the a/c when the windows get foggy?

to be fair my sister was trying to turn the a/c off last time it rained. she was like "isn't it cold enough in here? why do you have the a/c on?"
i wear a coat all winter and she doesn't, so when I drive i don't use the heater and she freezes. i don't really care because she gets free taxi service from me.
she also wants to earn money and keeps asking me to let her work on other people's cars, (im a shade tree mechanic) but won't stick around and learn stuff when I'm working on my car and she doesn't know much about cars. she can do oil changes with some help, but idk if she knows why the oil needs changed.

she is just 14 though.

 

[dishdude]

do people not know to turn on the a/c when the windows get foggy?

to be fair my sister was trying to turn the a/c off last time it rained. she was like "isn't it cold enough in here? why do you have the a/c on?"
i wear a coat all winter and she doesn't, so when I drive i don't use the heater and she freezes. i don't really care because she gets free taxi service from me.
she also wants to earn money and keeps asking me to let her work on other people's cars, (im a shade tree mechanic) but won't stick around and learn stuff when I'm working on my car and she doesn't know much about cars. she can do oil changes with some help, but idk if she knows why the oil needs changed.

she is just 14 though.

You can turn the heat up with the compressor engaged to stay warm while you remove moisture from the air.

 

[explorer2030]

You can turn the heat up with the compressor engaged to stay warm while you remove moisture from the air.

This is why I find it odd that hitting the ac button on and then off disables the compressor from running automatically based on wiper usage for the rest of the drive cycle. If someone got cold because the compressor was running, they could simply turn the temperature dial to heat and continue to get the benefit of air dehumidification.