Radiator fan issue

[FrankB]

I was driving to work a couple of weeks ago and noticed my temp start to rise. Dropped it in 7th gear and it went back down to the normal range. Drove home had to do the same thing at about 25 miles. I have a tazer so I tried the cool down mode and the fan did not turn on. I checked and made sure I have power to the fan and i have power. I let the Jeep idle until the temp gauge went above normal operating range and the fan did not turn on. I ordered and installed a new fan and still the same issue. I am assuming my temp sensor is good since the gauge works. I have done the A/C on high and the fan does not come on either. Any help would be much appreciated. I have JScan and other diagnostic tools. I know I’m overlooking something.

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[Heimkehr]

Food for thought:

Are the batteries in your 2018 JL the originals? If so, consider replacing both of them with quality AGM units. A battery (or two, in a Wrangler) that is reaching the end of its practical service life can cause any number of seemingly unrelated operating anomalies.

 

[scottijohn63]

I was driving to work a couple of weeks ago and noticed my temp start to rise. Dropped it in 7th gear and it went back down to the normal range. Drove home had to do the same thing at about 25 miles. I have a tazer so I tried the cool down mode and the fan did not turn on. I checked and made sure I have power to the fan and i have power. I let the Jeep idle until the temp gauge went above normal operating range and the fan did not turn on. I ordered and installed a new fan and still the same issue. I am assuming my temp sensor is good since the gauge works. I have done the A/C on high and the fan does not come on either. Any help would be much appreciated. I have JScan and other diagnostic tools. I know I’m overlooking something.

Make sure the screws on your water pump are tight. Check out this link.
https://www.jlwranglerforums.com/forum/threads/2-0l-water-leak.84706/.

 

[FrankB]

Food for thought:

Are the batteries in your 2018 JL the originals? If so, consider replacing both of them with quality AGM units. A battery (or two, in a Wrangler) that is reaching the end of its practical service life can cause any number of seemingly unrelated operating anomalies.

I have already upgraded the batteries.

 

[Jim1964]

I would spend a few bucks for a tech manual subscription. I think Mitchell for example is $30 for a year. You need the wiring diagram and diagnostic test procedure for the fan driver circuit. That’s a PWM fan so there’s more involved than just testing for power or lack thereof.

 

[FrankB]

I have tested the driver circuit and It will not actuate/turn on. I have the diagram for the fan circuit thinking there might be a relay in the circuit but there is not one that is shown. I have been tracing wires to see if there might be a broken one or loose connection. Going to start looking at the A/C side tonight when I get off work. Just trying to get some different perspectives to see if I’m missing something simple.

 

[NyRey87]

Ever figure this out? On Have a 20’ 2.0 with 24k Miles and the fan don’t like to come on. It was 75 degrees today and it was pushing 210-228 degrees according to the dash readout. The fam used to seem to come on once it hit 210. I don’t think it came on one single time today

 

[NyRey87]

Just called the service department at my local dealership and he said the update that came out in august changed time temperature at which the fan comes on. He said it won’t kick in till 248+ now. He said they changed it because people were complaining of the noise?? I told him I would rather have the noise and have my Jeep running cooler. He said my Jeep wasn’t running hotter. Which it obviously is because the damn fan won’t kick on! This guy was a tool at best. Anyone else heard this crap?

 

[TaiMc]

Just called the service department at my local dealership and he said the update that came out in august changed time temperature at which the fan comes on. He said it won’t kick in till 248+ now. He said they changed it because people were complaining of the noise?? I told him I would rather have the noise and have my Jeep running cooler. He said my Jeep wasn’t running hotter. Which it obviously is because the damn fan won’t kick on! This guy was a tool at best. Anyone else heard this crap?

This is the first I’ve heard of it. My fan kicks on around 210-221 depending on the type of driving/idling I’m doing.

Mine is an ‘18 so it likely wasn’t subject to their update.

 

[NyRey87]

This is the first I’ve heard of it. My fan kicks on around 210-221 depending on the type of driving/idling I’m doing.

Mine is an ‘18 so it likely wasn’t subject to their update.

Mine did too! Then I had to have them replace both my lower radiator hoses and they did the stupid update

 

[TaiMc]

Mine did too! Then I had to have them replace both my lower radiator hoses and they did the stupid update

ahhh…@13k miles my temperature thermostat sensor was faulty and it threw my gauge to the top and my fans wouldn’t stop coming on lol. Got the sensor replaced (I think before their update) in 2019.

Then Jeep overheated this year, but the fan was working bc i could hear it come on while my temp gauge rose. At that time i wasnt having the coolant screen on so idk what temp it rose to.

But needle went above middle and thats when i shut it off.
Is there a way to have them remove the update?

 

[NyRey87]

ahhh…@13k miles my temperature thermostat sensor was faulty and it threw my gauge to the top and my fans wouldn’t stop coming on lol. Got the sensor replaced (I think before their update) in 2019.

Then Jeep overheated this year, but the fan was working bc i could hear it come on while my temp gauge rose. At that time i wasnt having the coolant screen on so idk what temp it rose to.

But needle went above middle and thats when i shut it off.
Is there a way to have them remove the update?

This guy made it seem like there wasn’t but who knows what he knows

 

[Willys41]

Here is what I discovered and what I am working on
This is how the cooling system works or not working
The thermostat opens at 190 degrees
The cooling fans comes on at 1/4 speed at 221 and will only go fulls speed at 231 degrees
I have been trying to get control of the cooling system by adding a pusher fan on the condenser put this is what I found
Most cars including the jeep JK the condenser is mounted 1/4 to 1/2 in. from the radiator
On the Jeep JL the condenser is about 1 1/2 in. away from the radiator
I can get the pusher fan to shoot air though the condenser at 150 MPH put as soon as it hit the radiator the air blows out the large gaps between the condenser and radiator and NO air going through the radiator
Next step was to close the caps between the condenser and radiator to force the air through the radiator
So now with the gaps closed off I have about 15% of the air going through the radiator and the rest of the air is blowing back though the condenser and trans cooler
Two things wrong here. The gap between the condenser is to large and the radiator WILL NOT allow free flowing air to pass through it whether you are pushing air at 150 mph with a fan or diving down the road at 60 /70 mph and that is why you see a 40 to 50 degree swing in the coolant temps. You would thing driving down the road you are getting air passing through the radiator put you are getting very little to none until the fan kicks in and sucking the air through the radiator
I ordered a Mishimoto radiator (back ordered) it looks to have a more open core that will allow more free flowing air to pass through
I will install the Mishimoto and see how it goes
And NO. The radiator is not plugged in any way inside or out side. The jeep did this from day one . New in 2020
The Engineers got this one wrong and they know it from what I have read
UPDATE
The Mishimoto radiator made no difference in lowering the temperature
Step 2
Just installed the Rpmextreme JEEP JL PWM FAN CONTROLLER
This is a game changer . Here is how your fan will work with this device


Operation:

When the engine is running the PWM fan will run at a low Idle speed (15%).
When the module reads the engine temp it will command the fan to the desired %.

Fahrenheit

199 degrees = 30%

205 degrees = 50%

212 degrees = 75%

218+ degrees = 100%

Override inputs: These are optional inputs depending on if you ordered them.

These inputs will run the fan as long as the unit is powered up, the engine does not have to be running for these to work. You can use these in various ways.

Example:
When the ( VIOLET ) wire has 12 volts applied the fan will run at MAX speed.

I have only two days of testing put my temps now run at idle all day long 188 to 192
Normal driving I see 192 to 195 and 199 to 205 under hard acceleration put comes down real fast
This weekend I will be testing on a long up hill drive put I suspect of 215
I will keep you updated

info
Jon Schaefer RpmExtreme
205-631-8225 6774 Old Hwy 31N
Rpmextreme.com Gardendale, AL 35071

UPDATE
Just got back from a 60 mile round trip with up and down hills
One hill is about a mile long and fairly steep
Max temps on uphill clime WITH PWM module
Coolant 203
oil temp 206
Trans temp 195

Going down hill after 2 minutes
coolant temps 185
Oil temps 188
Trans temps 188 to 190

freeway driving 70 MPH
coolant temps 188 to 192
oil temps 188 to 190
trans temps 190 ( Note / The trans cooler I believe has a 190 degree thermostat so you will always see about 190 )

BEFORE the PWM module I would see going uphill
Coolants temp rise to 221 fans kick in at bout 15% and then if the hill was a long one go to 231 before the fan kicked in at about 75% . I have seen temps as high as 234
Oil temps would get as high as 225
Trans temps would hit 206

The JEEP JL PWM FAN CONTROLLER is a keeper
Now I need to add one to my wife's stock Rubicon

 

[Willys41]

UPDATE
Just got back from a 60 mile round trip with up and down hills
One hill is about a mile long and fairly steep
Max temps on uphill clime WITH PWM module
Coolant 203
oil temp 206
Trans temp 195

Going down hill after 2 minutes
coolant temps 185
Oil temps 188
Trans temps 188 to 190

freeway driving 70 MPH
coolant temps 188 to 192
oil temps 188 to 190
trans temps 190 ( Note / The trans cooler I believe has a 190 degree thermostat so you will always see about 190 )

BEFORE the PWM module I would see going uphill
Coolants temp rise to 221 fans kick in at bout 15% and then if the hill was a long one go to 231 before the fan kicked in at about 75% . I have seen temps as high as 234
Oil temps would get as high as 225
Trans temps would hit 206

The JEEP JL PWM FAN CONTROLLER is a keeper
Now I need to add one to my wife's stock Rubicon

 

[swampflyer]

UPDATE
Just got back from a 60 mile round trip with up and down hills
One hill is about a mile long and fairly steep
Max temps on uphill clime WITH PWM module
Coolant 203
oil temp 206
Trans temp 195

Going down hill after 2 minutes
coolant temps 185
Oil temps 188
Trans temps 188 to 190

freeway driving 70 MPH
coolant temps 188 to 192
oil temps 188 to 190
trans temps 190 ( Note / The trans cooler I believe has a 190 degree thermostat so you will always see about 190 )

BEFORE the PWM module I would see going uphill
Coolants temp rise to 221 fans kick in at bout 15% and then if the hill was a long one go to 231 before the fan kicked in at about 75% . I have seen temps as high as 234
Oil temps would get as high as 225
Trans temps would hit 206

The JEEP JL PWM FAN CONTROLLER is a keeper
Now I need to add one to my wife's stock Rubicon

any chance of some install pictures etc. Very good info for the jeep community. Where to purchase? Thanks

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