Driving home from work tonight I got "blind spot system fault", "cross traffic system fault", the airbag light came on (and would not blink but repeatedly go on and off), and when I parked to get out the power running boards did not deploy...

After searching forums the first two faults point to the module in the taillight, but how would that affect the other two electronic malfunctions?

Any ideas?

 

It helps if you EXPLICITLY identify what you're working on.

 

2016 F150 5.0 Lariat FX4 Sport SuperCrew. Black. Fully loaded.

 

Check your battery first.
Make sure it is fully charged.
Do a load test if you can.

 

X2 check your battery

 

Would be quite helpful to all if you now took that info and put it in your signature box so its there every time you comment.

Like this V

 

Done.

Update to the original problem. Started truck to go get battery and alternator tested, no codes or errors. Everything worked fine and normal. Ran fine, drove fine. Battery and alternator tested fine. For now I guess this is case closed, if anything funky continues I'll update this post with a new reply.

 

Nice job on the signature! How old is the battery? Not original I hope...connections clean?
Other things to check include all the wiring harness connectors under the truck. They are notorious for water getting inside them and causing all sorts of electrical gremlins.
After you discover the source of your current issue, go ahead and clean and inspect all the connectors, and apply some dielectric grease as preventive maintenance.
There are more threads related to this on the super duty forums, and some of the guys talk about water being trapped in the rocker panels. When that happens, the wiring harness that runs through there is literally floating in water. Obviously not a good situation either.

 

So after a few days of driving around with no issues, the gremlins came back. Current symptoms are:

- Blind spot failure, cross traffic failure
- airbag light on
- vents blowing air very low (just enough to feel it if you're paying attention)
- console HVAC controls are inoperable
- console radio controls are inoperable (steering wheel radio controls work)
- driver window inoperable (did not check others)
- power running boards again not functioning
​​​​​​
When I shut the truck off, the steering wheel and seat are very delayed to move as they do to allow room to get in and out of truck

If I turn the truck accessory power on (don't start it) the console radio and windows work again.

I'll start digging into connectors under the truck and in the rocker panels. Posting this up on case anyone has had these issues before and knows what / where the problem is.

Edit: found this older thread with the same problems I'm having, linking here for the next person that comes across this thread looking for possible solutions.
https://www.f150forum.com/f2/need-he...376664/index2/

 

When you see multiple codes like this, the first place to look is the age/condition of the battery. If you still have the OEM battery in your 2016, then the battery would be high on my list.

 

​​​​​​​Battery is 2 years old, and in post 7 I stated I had the battery and alternator tested, all checked out. The link I posted in post 9 people had all the same malfunctions I had and it was a wet or burnt plug. I'll check there first.

 

Just for grins, connect a battery charger and see if you get same results? Is it possible that when the battery was exchanged 2 years ago, the BMS was not reset, and it thinks it is dealing with an old battery? other than that, and if you are certain it is not the battery, I would start investigating, probably start with grounds. Good luck.

 

Geezus. People, look...

It.
Is.
NOT.
The.
Battery.

Took apart the taillights this past weekend, all sorts of water in the connectors. Dried them out, added dielectric grease to all connectors, plugged back in. Passenger side was definitely worse than the driver side - plugs on passenger side had some of the dreaded green / blue coloring on the female sides of the plugs. Dried out real good, greased them up, and away we go. No problems after several days of long trips (30+ minutes). Considering this case closed, until the taillights have to be replaced from corrosion. I understand I'm on borrowed time with these, but will push them as long as they'll go.

The blind spot modules did not appear to be damaged from the water in any way, only the plugs in the taillights themselves. I also drilled two holes in the bottom of the taillight housings to drain any possible future water accumulation.

Side note - someone has been in the taillights before for some reason, as I found that several of the tabs that hold the taillight in place are broken off. Also why I'm on borrowed time with these taillights until I can source new ones.

​​​​​​... The battery is still checking out good...

 

" Geezus. People, look...It. Is. NOT. The. Battery. The battery is still checking out good".

Glad you are making progress. And FYI, the reason members keep bringing up the battery and/or battery management system (BMS) is that issues such as yours (more often than not) tend to be related to static electricity, poor connections, poor battery voltage, or the BMS. Or any combination of the above. It might be of interest to you to research what the BMS is for and what it does. I think there is more to this system for you to learn before you jump on somebody for pointing this out. These new trucks are far more complicated than many would believe, especially where electronics are concerned.

Again, congrats for making some good progress and keep us posted on the results!

​

 

Not meaning to jump on any one or multiple of persons, just trying to get across the message that the battery (while possibly at fault for someone else for their issues with their electronics) was not the problem this time. Lol, especially after my post where I found a thread where people were having the exact same systems failing and figured it out to be the taillight connections and I linked to it. To be fair, it was more posted in jest, while hoping people that come to this thread get the message the battery is fine. The rest was just my "bandaid" repair for now on case anyone else stumbles across this in the future looking for a quick and cheap fix, if nothing else to test a repair before investing cash into a $400 taillight or a $1000 blind spot module (prices why I'm ok with the "dry and grease" method for as long as it lasts).