Air Conditioning quit working/ blowing

[exploringcarolina]

We were on our first trip with our 2024 F-150 STX, less than 500 vehicle miles, and the AC stopped working, but you could still hear the fan in the dash running.

Saw a Ford dealer from the interstate and stopped. Without an appointment, they pulled the F-150 in the shop and had it fixed & ready to go in less than an hour.

Here's what the work order said:

"Climate control system diagnosis, C/S can hear AC fan blowing, but has no air out of vents.
Verify concern self test no codes ran on Oasis perform SSM 52517 reprogram the HVAC Module Road test retest"

AC system has been working great since reprogram!

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[bkuhl]

New TSB 24-2168 released late May included all '21 - '23 F-150 models with an ICE. Wonder if they released another revision to include the '24s?

 

[bkuhl]

oh, looks like SSM 52517 is the same thing, just for 2024 models...

 

[Steve Feldkamp]

My 2021 hadn't worked correctly sense I had it. The last service update finally fixed it last month. Doesn't freeze up and the left vent works correctly all the time.

 

[AB_GA]

My 2021 hadn't worked correctly sense I had it. The last service update finally fixed it last month. Doesn't freeze up and the left vent works correctly all the time.

Was it a computer update only?

 

[Steve Feldkamp]

Was it a computer update only?

Yes, from the latest tech bulletin on the issue.

 

[Steve Feldkamp]

Yes, from the latest tech bulletin on the issue.

t

 

[Airborne_Ape]

Fun Times

Tools:
T20 torx
T10 torx
Pick

Pro tip: remove the Transfer Case Control Module first (2 x 10mm) to access the rear screw on the blower motor.

We got hit with a high humidity heat wave in the North East this week and I ran my AC more often than usual. I ran into rare problem that no one else has talked about and in the process of solving it, I inadvertently ran into other issues and solved those too which may help others in their troubleshooting.

Instead of creating a new thread I'm adding to this old one which contained the most helpful content.

My main issue wasn't any of these but they are good to read through and correct along the way.

SSM 52517
TSB 19-2345
TSB 24-2168

My initial symptoms were the distinct faint sound of boiling and when making tight turns (pulling G's) or driving on rough roads what sounded like pressurized gas escaping.

I quickly believed I was hearing an intermittent leak in my Evap core which is common on multiple Generations of F150's.

It turns out, what I was actually hearing was AC condensation boiling against the heater core and AC condensation hitting the blower motor when making some turns.

The reason why AC condensation back-filled was because some wasps crawled up in my AC drain and died in there which took a while to figure out.

The AC condensation was draining to the pavement but not at sufficient flow rate to keep up in our high humid heat wave. When I finally figured it out and got the debris out with a screw driver a little tsunami of insect parts came gushing out.

I flushed it out manually afterwards and stuck a borescope through AC drain to confirm there's no more mother nature bits stuck inside the HVAC housing.

The crazy thing is, my Blower Motor Control Module 12V 40A was completely submerged under water this entire time (likely a week) and worked fine LOL. The amount of conformal coating on the PCB did its job, but how the heck it didn't blow the fuse is a mystery.

Fuse #13 in the BJB 40A Green.

I took a video of the amount of water that poured out of the ECU. I was blown away this didn't fail or take out its fuse in the BJB.

Drained it, cleaned it up, replaced the damaged cap and tossed it back in.
I couldn't belive it worked! ..... But then when it died a day later I wasn't surprised.

Turns out, after draining out the control module this first day, everything then oxidized overnight. Probably related to the CAP that burst while it was submerged.

So, I reassembled my Blower Motor three times in the last 48 hours.

• The first time, I dried it out and replaced the bad CAP.
• The second time I scrubbed off the oxidized crusty crud that formed.
• It took a third time to realize the 12V 40A circuit clips are free floating and need to be tapped down or else it will intermittently connect to the PCB and periodically fail its power on self test.

Unfortunately I can't get to the blower bearings due to the plastic welds and amount of rust that has formed on the blower shaft.

My goal at this stage is to keep it going just long enough to order a replacement from Ebay or a junk yard and get through a few weeks.

13 Gen and 14 Gen use the same blower motor and control module sold as an assembly, so they're ubiquitous and easy to find:

Part Number: FL3H-19846-AG
There's loads of these on Ebay

The key lesson is:
If you have intermittent or permanent AC Blower Motor failure, I'd first check these janky free-floating clips and the spring tension ground under the PCB tray.

Some blower motor failures out there may be solely because these just need a dab of solider or a minor tension adjustment. Start to finish it takes about 30 minutes to correct and the removal of 5 screws.

So far this repair has cost about 80 cents and two days of my time. A used replacement part is high on my agenda; although it's not critical.

My local Pick and Pull options are hit and miss for F150's. Napa has third party replacements for $500 CAD. My Ford Dealer wanted $560 CAD for a direct replacement, keep in mind that's with a correct diagnosis though. Some dealerships would be more than happy rush a diag and charge $5K+ for an HVAC unit replacement over these issues.

There's aftermarket options on Amazon, but the ECU looks like something that should be kept OEM if at all possible. For example: I wouldn't want to order a cheap one without the conformal coating and have it burst into flames if condensation makes it up there again.


@Snakebitten keep's coming up in similar AC threads, so I tagged as an FYI.

 

[Snakebitten]

Fantastic post.
And it is amazing both the wasps role in the malady, and the fact it worked while submerged.

Your tenacity is impressive!

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