3.6L Radiator Fan Problem?

[SitKneelBend]

Is that the new fan? When I ran the test with AlfaOBD my fan did the little left right shimmy before starting.

No, that's the old one still. New one should ship today. I'll be sure to update when it's in...

 

[sblack33741]

I used the Dorman aluminum unit. Six months no issues so far. It’s pretty good quality and comes with all the seals and gaskets. I think it’s actually a bit more expensive than the OEM unit not lol

If you have any issues, let us know. There are a lot of us out here who will need that information. Lol

 

[Atcer2018]

If you have any issues, let us know. There are a lot of us out here who will need that information. Lol

Sure will. Only thing I’ve seen is slightly higher temps since I’ve replaced the oil cooler unit. I have no idea if the higher temps are from the Dorman unit or something else. I’ve read some chatter on the Jeep forums that the all aluminum cooler housings don’t dissipate heat as quickly as the plastic housings. I have no idea if this is an actual fact but it was interesting reading.

 

[SitKneelBend]

So the fan arrived today and it was "almost new in box" but it came with a broken mounting tab. For $200 I'm not even gonna bother the seller about this as I'm still winning (I would have bought it if they advertised it that way probably)! It works too, but oddly enough, the AlfaOBD commands for the fan still don't spin it up BUT running the AC spins it up nice and fast (and constant). I'm going to see how easy it might be to swap the fan housing from my old one so I have two good mounting tabs.



Edit: I let the seller know in case they took out insurance on it and they gave me a $20 refund so only $180 for a new OEM fan!

 

[SitKneelBend]

3 5mm Hex screws and a couple cable clips and the fan module drops right out of the shroud.



The fan definitely works better than the old one. Temps were 90 degrees and with the AC running after a 30 minute drive then idling the temperatures were much better...



But the fan still only kicks on at 228 to cool the coolant to 219 then cuts off again.

Does anyone know if you can see the fan set points in AlfaOBD?

 

[SitKneelBend]

I tried the Fan1 and Fan2 options and they produced nothing. AlfaOBD shows the procedure failed.

Radiator Cooling Fan PWM Duty Cycle did NOT physically activate the fan. It produced two different relay cycles and the procedure ended. In other words when I pushed START a double click of a relay was heard from the under hood fuse box. As soon as the first relay clicked twice another relay clicked twice and then procedure ended. It showed procedure completed in AlfaOBD.

Electric Fan Command in PWM turned on the fan and ran it from slow to full speed before turning off. The sequence of this test was after pressing start there is a relay click, fan spools up to high, second relay click and fan spools back down. AlfaOBD shows procedure complete.

Hey, did you hear a high pitched electronic noise/whine between the relay clicks that runs the duration of the test or just relay clicks?

Video for reference...first click is missing but there was one at the start.

June 13, 2024

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[Atcer2018]

Hey, did you hear a high pitched electronic noise/whine between the relay clicks that runs the duration of the test or just relay clicks?

Video for reference...first click is missing but there was one at the start.

June 13, 2024

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Yes the whine is there for the duration of the PWM duty cycle test and the electric fan command on test. I just checked it and the whine starts when the procedure command is started by AlfaOBD. Even though the PWM duty cycle doesn’t actually start the fan the whine starts, relay clicks, 10 seconds later another click and the whine stops. The command on test follows the same pattern except the fan spins up to high and shuts off along with the whine.

 

[SitKneelBend]

Yes the whine is there for the duration of the PWM duty cycle test and the electric fan command on test. I just checked it and the whine starts when the procedure command is started by AlfaOBD. Even though the PWM duty cycle doesn’t actually start the fan the whine starts, relay clicks, 10 seconds later another click and the whine stops. The command on test follows the same pattern except the fan spins up to high and shuts off along with the whine.

That's good to hear. With mine not running the fan with this command I feared this was some kind of electrical short noise. That being said, I see that folks have said their HP tuner reports that "Low: 210°F. Med : 224°F. High 234°F" but mine doesn't turn on that way and from what I gather from looking nearly nobody's does. 228 on what sounds like medium appears to be the common thread I can glean from anecdotes. I'm not sure I'm going to do much more on this except maybe look into a tuner, I have a 2014 so apparently my PCM is the last year they were unlocked which "should" make it a little cheaper for me.

To see if I can get at when my truck is actually commanding the fan to be on via PWM I'm going to try out AlfaOBD's Plotted Data Gauge Scans. If I can see that the gauge is asking for low at 210 but the fan is not turning I'll know something is up (I think).

 

[Atcer2018]

That's good to hear. With mine not running the fan with this command I feared this was some kind of electrical short noise. That being said, I see that folks have said their HP tuner reports that "Low: 210°F. Med : 224°F. High 234°F" but mine doesn't turn on that way and from what I gather from looking nearly nobody's does. 228 on what sounds like medium appears to be the common thread I can glean from anecdotes. I'm not sure I'm going to do much more on this except maybe look into a tuner, I have a 2014 so apparently my PCM is the last year they were unlocked which "should" make it a little cheaper for me.

To see if I can get at when my truck is actually commanding the fan to be on via PWM I'm going to try out AlfaOBD's Plotted Data Gauge Scans. If I can see that the gauge is asking for low at 210 but the fan is not turning I'll know something is up (I think).

View attachment 544725

That’s a great idea if you can pull those graphs for the command temps. I’d love to know what temps trigger the different speeds.

I concur with the 228F as mine comes on at 228F but i thought it was at the high setting. I wonder if there is a way to tell the speed of the fan by reading current draw. It is 90F here today and on a 30 minute trip I had no issues with temps in town or on the highway. The only issue I get is long trips at highway speeds with the AC running continuously, the temps creep up into the 220’s. At 228F they will drop back down to the high 210’s but fluctuate constantly. If I turn the AC off the temp slowly goes back to 204F. I’m not so worried about running at 70mph with 220’s but the oil temps don’t inspire confidence as they rise above 230F.

Do you know what controls the fan speed? Is it a relay or the BCM? Any luck finding AlfaOBD fan settings?

 

[SitKneelBend]

That’s a great idea if you can pull those graphs for the command temps. I’d love to know what temps trigger the different speeds.

I concur with the 228F as mine comes on at 228F but i thought it was at the high setting. I wonder if there is a way to tell the speed of the fan by reading current draw. It is 90F here today and on a 30 minute trip I had no issues with temps in town or on the highway. The only issue I get is long trips at highway speeds with the AC running continuously, the temps creep up into the 220’s. At 228F they will drop back down to the high 210’s but fluctuate constantly. If I turn the AC off the temp slowly goes back to 204F. I’m not so worried about running at 70mph with 220’s but the oil temps don’t inspire confidence as they rise above 230F.

Do you know what controls the fan speed? Is it a relay or the BCM? Any luck finding AlfaOBD fan settings?

I found the fan type in the Pentastar_Info.log for AlfaOBD, it is "Linear Pulse Width Modulation (PWM) Fan Relay System Equipped: Yes"



I'm not sure what controls the fan but I think it's the PCM. I've traced the N27 circuit of the PWM signal from the fan (Red Wire) to a connector under the TIPM but not on the TIPM for the PCM (Transitions to a Dark Blue/Gray wire on the PCM side). I think I saw some corrosion on two of the pins in their and I'll be opening it back up to see if it's one of the pins servicing the fan signal. I also found that nearly every single fuse and relay in my fuse box was not all the way seated so pushed everything down while I was in there. In addition, you can see the thicker red 12v power wire for the fan itself running under/into the TIPM right where that 80amp fuse is above in the fuse box.



I'm going to try and graph it with AlfaOBD tomorrow morning while I run some errands. I'll let you know what I find. So far for me, running the AC is what keeps everything cooler (oil temps too) as the fan runs constantly. I'm only guessing at what I think the 228 fan speed is though because I feel like I've heard the fan on high and it's louder than that but I could be misremembering...

As far as what percent it's asking for, if it works that graph will show 0%-100% with .5 being 50% and 1 being 100% (I think).

 

[Atcer2018]

I found the fan type in the Pentastar_Info.log for AlfaOBD, it is "Linear Pulse Width Modulation (PWM) Fan Relay System Equipped: Yes"

View attachment 544750

I'm not sure what controls the fan but I think it's the PCM. I've traced the N27 circuit of the PWM signal from the fan (Red Wire) to a connector under the TIPM but not on the TIPM for the PCM (Transitions to a Dark Blue/Gray wire on the PCM side). I think I saw some corrosion on two of the pins in their and I'll be opening it back up to see if it's one of the pins servicing the fan signal. I also found that nearly every single fuse and relay in my fuse box was not all the way seated so pushed everything down while I was in there. In addition, you can see the thicker red 12v power wire for the fan itself running under/into the TIPM right where that 80amp fuse is above in the fuse box.

View attachment 544751View attachment 544752

I'm going to try and graph it with AlfaOBD tomorrow morning while I run some errands. I'll let you know what I find. So far for me, running the AC is what keeps everything cooler (oil temps too) as the fan runs constantly. I'm only guessing at what I think the 228 fan speed is though because I feel like I've heard the fan on high and it's louder than that but I could be misremembering...

As far as what percent it's asking for, if it works that graph will show 0%-100% with .5 being 50% and 1 being 100% (I think).

View attachment 544753

Yes please keep us updated, looks like you’re onto something. Wish AlfaOBD had the ability to change fan settings. Thanks for the tip, I’ll be checking my fuses tomorrow lol

 

[SitKneelBend]

Yes please keep us updated, looks like you’re onto something. Wish AlfaOBD had the ability to change fan settings. Thanks for the tip, I’ll be checking my fuses tomorrow lol

Edit: Looking at how the fan operates I suspect most folks are wrong about when their fan actually turns on. My readings match reports. At no time did I see the fan come on without the A/C being on under 228 degrees. I suspect the values shown in Tuners are the default values set by the makers of the tuners and those values don't exist in the PCM/ECM. The A/C fan control itself appears to be far more dynamic than expected too and I suspect vehicle speed and some A/C pressure/temperature input is at play when the fan turns on. I'd really love to see someone replicate this on a 2013-2014 RAM 1500 and on any 2015+ RAM too as there were major PCM changes in 2015 from my research.

I'll post in more detail later this weekend but long story short, it works. If you try to replicate select these three things to monitor (I was wrong about the scale it's dynamic once it starts based on the values recorded). Press the play button in the top right hand corner to start logging...

 

[Atcer2018]

Edit: Looking at how the fan operates I suspect most folks are wrong about when their fan actually turns on. My readings match reports. At no time did I see the fan come on without the A/C being on under 228 degrees. I suspect the values shown in Tuners are the default values set by the makers of the tuners and those values don't exist in the PCM/ECM. The A/C fan control itself appears to be far more dynamic than expected too and I suspect vehicle speed and some A/C pressure/temperature input is at play when the fan turns on. I'd really love to see someone replicate this on a 2013-2014 RAM 1500 and on any 2015+ RAM too as there were major PCM changes in 2015 from my research.

I'll post in more detail later this weekend but long story short, it works. If you try to replicate select these three things to monitor (I was wrong about the scale it's dynamic once it starts based on the values recorded). Press the play button in the top right hand corner to start logging...

View attachment 544761

Your findings would match what I’ve experienced with my 2018. I’ve never seen my fan come on without the AC on or reaching 228F. I thought I had a problem with the low speed activation or the fan itself. It makes sense that any setting other than the 228F trigger is written into the values of an aftermarket tune.

 

[SitKneelBend]

That’s a great idea if you can pull those graphs for the command temps. I’d love to know what temps trigger the different speeds.

I concur with the 228F as mine comes on at 228F but i thought it was at the high setting. I wonder if there is a way to tell the speed of the fan by reading current draw. It is 90F here today and on a 30 minute trip I had no issues with temps in town or on the highway. The only issue I get is long trips at highway speeds with the AC running continuously, the temps creep up into the 220’s. At 228F they will drop back down to the high 210’s but fluctuate constantly. If I turn the AC off the temp slowly goes back to 204F. I’m not so worried about running at 70mph with 220’s but the oil temps don’t inspire confidence as they rise above 230F.

Do you know what controls the fan speed? Is it a relay or the BCM? Any luck finding AlfaOBD fan settings?

Found this diagram in another thread, no relays involved for our Linear PWM fan control and it is wired directly to the PCM for the fan control signal...

 

[SitKneelBend]

I had another revelation today while graphing the data from the PCM. The fan comes on very infrequently and it appears to be by design. I was initially troubled when Turing on the A/C and not seeing the fan come on while traveling at about 55-75mph. I thought maybe I had found a problem with the fan's control BUT I noticed when I turned on the A/C the temperatures were dropping fairly quickly even though the fan was not showing any output. Then it clicked, while in motion the AGS is opened and forced out of aerodynamic mode when you command A/C, the fan would not come on again until the truck came to a complete stop and stayed below about 20MPH. On an 88 degree day the truck cooled from 219 all the way down to 188 with only the AGS opening (no PWM fan) over about a 3-5 mile run. When the fan is called to cool at low speeds or idel with the A/C on, it will run from about 28%-31% speed. You can see that here on this graph:

Highway speeds down to neighborhood speeds mostly AGS cooling after turning on the A/C (700 time is where I slowed from 45 and pulled into my neighborhood)



IN addition, I've confirmed the 228 and idle setting that the fan turns on at and it appears to turn off again at 221-222 degrees. Surprisingly enough, when the truck gets to 228 the fan is called on to run at about 20% speed. You can see that cycle here 3 times on this graph (sitting in a drive thru idling no A/C on):

 

[Atcer2018]

Thank you for investigating this and posting the results. Gives me a better understanding of how the
e-fan system works. Now I have to figure out why my temps rise with the AC on at highway speeds instead of falling like yours. I’ve deleted the AGS louvers but the system is still in place so the PCM should be sending the same commands to the fan. My temps are very consistent between 195-205 in all conditions except with the AC on at highway speeds over about 65mph. My temps will run up into the 220’s and stay there till I slow down or turn the AC off, then return to the 195-205 range. Any ideas why? Maybe I have an AC problem not a cooling problem.

 

[SitKneelBend]

Thank you for investigating this and posting the results. Gives me a better understanding of how the
e-fan system works. Now I have to figure out why my temps rise with the AC on at highway speeds instead of falling like yours. I’ve deleted the AGS louvers but the system is still in place so the PCM should be sending the same commands to the fan. My temps are very consistent between 195-205 in all conditions except with the AC on at highway speeds over about 65mph. My temps will run up into the 220’s and stay there till I slow down or turn the AC off, then return to the 195-205 range. Any ideas why? Maybe I have an AC problem not a cooling problem.

Have you tried cleaning the condenser coils? I'd think that with how heavily the AGS is used in place of the fan to moderate temperatures that improving the amount of air pushed through by driving might solve your issues. I'm not super familiar with the system in vehicles but that's something that gets done annually on my home units to keep them operating cooler and more efficiently. If you graph your stuff out I would be happy to make comparisons for you. In addition, I have noted that the fan speeds requested are far more dynamic than I originally thought and it appears to take into consideration outside temperatures as well somehow possibly.

I'm pretty sure I've busted the myth that these fans come on based on simple algorithms of coolant temperature though and they have put a lot of thought into efficiency and cooling demands on the system. Now that I know more about what is happening, I'm surprised at how much cooling gets accomplished somewhat passively and realize my old fan is probably good still. I'm guessing the PWM fan command in AlfaOBD might be a bug for my model year too and I'm going to ask the developer to look into it when he can (not too concerning though since I can watch operation on the graphs).

My next project is seeing how much different I can make intake air temperature and pressure by using a Frankenstein intake tube I have mated to the stock filter box now that I know AlfaOBD can collect this data! I had this on before but took it off for warranty work before it expired.

 

[SitKneelBend]

Hey @Atcer2018 , I forgot I had another question for you since I know you have been in there...is your thermostat housing aluminum? Mine is metal but every video I see for the 3.6L has a black plastic thermostat housing?

 

[Atcer2018]

Have you tried cleaning the condenser coils? I'd think that with how heavily the AGS is used in place of the fan to moderate temperatures that improving the amount of air pushed through by driving might solve your issues. I'm not super familiar with the system in vehicles but that's something that gets done annually on my home units to keep them operating cooler and more efficiently. If you graph your stuff out I would be happy to make comparisons for you. In addition, I have noted that the fan speeds requested are far more dynamic than I originally thought and it appears to take into consideration outside temperatures as well somehow possibly.

I'm pretty sure I've busted the myth that these fans come on based on simple algorithms of coolant temperature though and they have put a lot of thought into efficiency and cooling demands on the system. Now that I know more about what is happening, I'm surprised at how much cooling gets accomplished somewhat passively and realize my old fan is probably good still. I'm guessing the PWM fan command in AlfaOBD might be a bug for my model year too and I'm going to ask the developer to look into it when he can (not too concerning though since I can watch operation on the graphs).

My next project is seeing how much different I can make intake air temperature and pressure by using a Frankenstein intake tube I have mated to the stock filter box now that I know AlfaOBD can collect this data! I had this on before but took it off for warranty work before it expired.

View attachment 544904

Thank you for the data logging offer. I will try to do as you have done and get the information for my vehicle.

I have cleaned the radiator and condenser. I cleaned them once before when I switched over to LED lighting with grill off. I cleaned them again when I deleted the AGS. Used the spray cleaner in a bug sprayer pump that I use for my home AC units. Spray on, it foams, wait ten minutes, rinse off type. The condenser looked pretty clean from the get go as I assume the AGS offers a degree of protection from excessive bug guts and debris.

Your data does dispel the belief that the e-fan is preset to switch on and off via a PCM program using only designated temperature points. As dynamic as you’ve found the system to be I wonder what other systems feed the PCM data. I remember reading some time ago a post in another thread that something in the AC system feeds info to the PCM for cooling commands. I dismissed it at the time and now can’t find the post.

I see your modified air tube. What is the goal of your experiment? Lower intake charge temps?

 

[Atcer2018]

Hey @Atcer2018 , I forgot I had another question for you since I know you have been in there...is your thermostat housing aluminum? Mine is metal but every video I see for the 3.6L has a black plastic thermostat housing?

Mine is the black plastic with plastic bleeder screw. I wonder if yours is OEM as I know Dorman offers an aluminum housing.