Hey all, been ignoring this problem for a bit and just not using climate control control or A/C.
2016 f150 3.5.
As soon as I hit my A/C, fans get very loud. I can’t even be in a drive thru or talk to someone outside. I’ve already confirmed my fan relays work fine.
I pulled some forscan numbers last spring with the truck cold and in the driveway.
I’m not entirely sure how to read this and understand what the problem is. Was hoping to identify some starting points to look at and have someone with the proper equipment assist.
Not sure why the recirc shows an “Error” either. If there’s any other tests I should do and get from forscan, I can as well. Thanks!

 

I assume you're talking about the radiator fan.
Not sure where you are located, but in here in AZ when it gets above 90F, the fan on my truck runs pretty much all the time.
Once it gets below 90F outside temp, it runs as needed.

 

Your fans are being commanded to run on high speed by the PCM, probably because the AC pressure is around 350 psi. There are other parameters built into the PCM's programming that will also trigger high speed fan operation.

You might want to evaluate your system AC pressures with an external set of gauges to see if the sensors are correct or not. If correct, that's an unexpectedly high pressure that probably should be evaluated.

As for the fans being loud when they're operating at full speed, lot's of complaints about that. Usually replacement of the fans takes care of it per reports.

 

Same here in the Gulf South. 90+ and high humidity the fans are running on high most of the time for the A/C. Living in the south the sound of the fans don;t bother me they actually reassure me that the truck has good cooling capacity. Walk through any parking lot around here and every vehicle's cooling fans will be running full blast. They maybe loud but the air is ice cold even when it's just sitting there idling in traffic with the temp showing 100.

 

Yeah, the system definitely thinks the refrigerant is hot at 350psi. At 90ºF, R134a should be about 250-275psi, with the low side about 50-55psi.

 

There is a TSB out for this - I've been having the same issue last summer and this year.

I don't know how to link to it - I have it printed out. The TSB number is 21-2250 - the title is poor A/C performance AND/OR engine cooling fans running continuously.

I had my dealer do the diagnosis and it turns out that mine needs the evaporator replaced as per the TSB. This entails removing the entire dash.

I haven't had it done yet as the dealership just changed hands and will be a couple weeks before he can enter the warranty claim (ESP).

I found a link here -

https://www.tsbsearch.com/Ford/21-2250

 

I had the same issue with my 2015 platinum model and the shop said fans are running full speed with AC on because of a failed evaporator. The dealership quoted me $1500 to replace it which does require the removal of the dashboard. I did further research and took a chance at what I found which was to replace a faulty thermal expansion valve on the firewall. The TXV was around $50 and took about an hour to replace. The system Has to be evacuated first and then recharged afterwards but it sure took care of my high speed fan problem and the AC works as it should.

 

Before ripping into your A/C system, what is your OAT? Sounds normal to me. Do not get over your ski’s. Perhaps, Put Down the Computer and Back away from your truck.

 

Both a sticking TXV and a flaky EVAP_Temp sensor (among other things) are possible causes of the gross symptom of the fans running on high speed when they probably, in the absence of a malfunction, would not do so.

That's why i recommended that someone evaluate the system properly instead of going off on a rabbit trail based on simple anecdotes.

 

Agree. READ THE DAMN PRESSURES. If you don't know how to do that, or don't understand how the charts work, let someone that does do it. It's dirt simple once you understand it, but until then it might as well be magic. You can't diagnose most HVAC systems on sensor data alone, and even if you could, you still need to verify the sensor data with pressure and temperature checks.

Evaporators don't tend to fail, they tend to get blocked by something else that failed. If you're having to replace an evaporator or condenser, the whole system needs to be checked for contamination to prevent ending up in the same situation down the road.

Sometimes an evaporator or condenser WILL fail by springing a leak. Not common, but it does occur, will manifest as constantly losing refrigerant.