SpencerPJ

If you didn't reset the battery monitor, give it a few days to recognize the state of charge. They are very finicky. A nice 1 hour interstate drive might do wonders for your truck.

HoustonScrew

my 2018 5.0 is doing the exact same thing as yours...it just started this week. I have to play with floor, defrost and front to finally get heat flowing into the cab. I haven't done any tearing apart, but have a 6 month old new battery, 65k miles and *** disabled through forscan. It is an STX so not much of electrical for the truck.

my guess is that i have an actuator for the blend doors going bad. sucks for such a young truck.

Home2#7

Post #1 is very good, detailed description of your symptoms. The GUESSES as to the cause for all this (batt, rodent, gas) are all good GUESSES. However to really diagnose your issues, a (complete) list of DTCs from all modules may be required to focus in on the issue(s). My initial GUESS is something electrical, but there is a LOT of wire in these new trucks!

CTru

Thanks for the reply! I thought maybe my issue had been solved after I reset the battery control module...However, every time I start my truck my fans will still kick on for 10 seconds or so. They then shut off for awhile but then will come back on after about 20-30 minutes and then stay on for awhile (minutes). I haven't had a chance to do a long test drive yet to see if this problem persists longer.

Side note, my other issues do seem to be resolved or at least haven't occurred again.

I ran a regular DTC scanner and got no codes. I ran another scan using forscan and only got two codes listed below.
"Code U2102 - Control Module Configuration Incompatible. Status: - Previously Set DTC - Not Present at Time of Request, -Malfunction Indicator Lamp is Off for this DTC, Module: Steering Column Control Module"

"Code B137F - Steering Wheel Left Switch Pack, Additional Fault Symptom: - Component Failures, Status: - Previously Set DTC - Not Present at Time of Request, -Malfunction Indicator Lamp is Off for this DTC, Module: Steering Column Control Module"\

Sorry if I gave unnecessary info above, just tried to type out everything for each DTC.
I believe these may be related to the left steering wheel buttons (arrows) as the "up" arrow will sometimes not work correctly and functions the same as the "ok" (center) button.

Home2#7

Great to see you making progress! What happened between your Post #10 and your Post #14? Did you take SpencerPJ"s suggestion? Your DTCs appear related to your left steering wheel switch pack as you indicated. Because all but one of your issues "haven't occurred again" , I do not think you have a wiring issue. Maybe some of the threads (with similar symptoms) like this one will help. https://www.f150forum.com/f118/engin...-speed-489652/

Good Luck

CTru

Yah I reset the battery control module as they suggested and haven’t had any issues with my airflow from vents since then. I need to go on a longer drive to really test it though.

I have been looking at those threads and not really sure what to think or try to diagnose next. Thank you for the input!

CTru

Also, random question. Should my cooling fans always be running, or do they run intermittently? My fans currently only run in high speed on an intermittent level. Should my fans be running in low speed most of the time? Just wondering if there is something wrong with the low fan speed control circuit

Home2#7

Lots of questions! Just some info - Low fan (LFC) is both fans at a lower rotation speed (they are sharing one 12 volt source). High fan (HFC) is both fans at high rotation speed (they have their own individual 12 volt source). So if one fan motor or LFC is "bad" only ONE fan will run when high is requested and NO fans will run when low is requested. PCM tells the fans when to turn on via LFC and HFC. Forscan has data PID for both in PCM module and can be monitored for "ON" or "OFF".

CTru

Thank you for the reply! So I found this cooling fan relay logic document for a 3.5L Ecoboost, so I don't know how much different the system is in a 5.0. I checked out the fuses that could be bad based on this and they all seem fine.

https://www.f150forum.com/attachment...elay-logic.pdf

Last night I locked my truck and let it sit overnight (to let it sleep as some people have suggested). I started it up and the fans did not run at all (first time that has happened in awhile). I drove into town (about 15 minutes), and the fans never came on. I left all my heat/ac off for the drive. I stopped and filled up with gas. Then when I restarted the engine the fans started immediately turn on in high and stayed on for the remaining 10 minutes into work (all heat and ac still off). Ambient air temps were around 35 degrees this morning. Average highway and city driving, definitely not working the engine hard.

Home2#7

I reviewed the logic document (comprehensive) and I think it would apply to your 5.0 L as well. Based on your last para in Post 19, I think the PCM is receiving an input from other systems that cause it to turn on the rad cooling fans. From my 2015 Workshop Manuel I copied - "The PCM monitors certain parameters (such as engine coolant temperature, vehicle speed, A/C ON/OFF status, A/C pressure) to determine engine cooling fan needs." Would think your 5.0 L parameters would be similar. I think I would try to investigate if engine coolant temp or A/C pressure were the cause of your issue. (You had A/C OFF and speed after the gas station high enough, so these two hopefully are not the issue). Hope some of this helps. Does anyone KNOW of other things that turn on the red cooling fans?