Radiator Fan Not Working

[2013megacab]

On my latest trip it seemed the truck was running a little warmer than it should be. On a part of my drive, the water temperature gets up over 206 and, in the past, the radiator fan would come on (or speed up), the temp would cool down to 203 and the fan would shut off. This time the fan did not come on. I checked the fuse box and the manual said F01 was for the "radiator fan controller (if so equipped)". I do not have an F01. I wonder if, as part of a recent shop visit the fuse was removed for some reason and not replaced, or is my truck not "so equipped"? How can I tell if I am supposed to have F01? My build sheet only lists "Heavy Duty Engine Cooling", and "Transmission Oil Cooler".

Assuming I am not supposed to have F01, how can I find why the fan is not operating? I checked F03 and it is good. Is there a thermostatic switch somewhere I can short to see if the fan comes on?

Edit: I assumed there was an auxiliary fan I was hearing. Maybe it is just a fan clutch.

Thanks,

Al

 

[AH64ID]

That F01 is likely for the electric fan on the Hemi.

My fan doesn’t really come on until 213-215°. Above 225° is too hot.

The 190° thermostat opens at 190°, but isn’t full open until 207° so running around 206° means that the cooling system isn’t being tasked too hard.

With the EGR cooler and lower capacity of the 6.7 block the 6.7 runs up against full open on the thermostat pretty easy when towing.

No thermostatic switch. The ECM controls the fan based on lots of parameters. If your fan isn’t working it should throw a code, but it may not illuminate the CEL so you would have to scan it to see the code.

 

[2013megacab]

Thanks for the help. In retrospect, the fan may have come on at 2008 or a little higher. In those cases I was climbing a hill to my house and not towing. I assumed it was electric, but maybe it was just a fan clutch. I read the codes today and there were none. Earlier last week I was towing, truck bed was full, but stuff was not very heavy. I was towing the Aiirstream (9000#) up a grade into Blowing Rock NC grade averaged around 8% but a coupe of short sections hit 15%. The coolant indicated temperature got up to about 215, but I never heard the fan come on.

 

[AH64ID]

Thanks for the help. In retrospect, the fan may have come on at 2008 or a little higher. In those cases I was climbing a hill to my house and not towing. I assumed it was electric, but maybe it was just a fan clutch. I read the codes today and there were none. Earlier last week I was towing, truck bed was full, but stuff was not very heavy. I was towing the Aiirstream (9000#) up a grade into Blowing Rock NC grade averaged around 8% but a coupe of short sections hit 15%. The coolant indicated temperature got up to about 215, but I never heard the fan come on.

Only 215° tells me it likely came on, but probably not full. It really starts to roar above 218°.

If you still doubt it after some driving scan it for codes.

You should also be able to hear it run when using the A/C at low speeds.

 

[sag2]

Just got back from vacation towing the trailer in 90-100 weather. Fan starts to come on at about 215. Never got above 220 and the fan was roaring pretty good until about 210. Then repeats on long grades.

 

[2013megacab]

I must be mis-remembering the turn on temperature then. So far this trip, climbing up to the house not towing (I have never towed up to the house) the temperature never gets above 205, but it is only in the mod-70s.

Thanks everyone for the comments.

Al

 

[Ozymandias]

The Fan isn't an ON/OFF unit, the speed of it is commanded from the ECM and is independent (more or less) from the engines rpm.
It is PWM controlled.