For the second time in two weeks, I have noticed within about 15 minutes after parking my truck and shutting it off, the exterior lights are flashing. It only does it a limited amount of times, as each time I have noticed it, it eventually stopped by itself. I can say for sure it was flashing for at least 10 seconds or more.

The first time, I thought it was the hazard lights flashing, and that I must have somehow accidentally hit the button when exiting the truck. I noticed them flashing after getting home from work. I had just parked, gone inside to let the dog out, and then came back out to get firewood when I noticed them flashing. I immediately thought wtf, there is no way I left the hazards on, and went to open the door to see. It was locked, and when I pulled on the handle the lights stopped flashing. I went inside, got the keys, unlocked the truck, turned on the hazards and turned them off again. The first thing I noticed was the timing of the flashing; the hazard lights flash at a pace much slower than the pace the lights were actually flashing when I came out and saw them. In fact, I would say they were flashing twice as fast as the normal hazard lights flash. It was fast enough that the tail lights were just barely extinguished before turning on again, where as the hazards flash with a pause between turning on again.

I could not identify any issue that would cause this, chalked it up to a weird fluke, and went on with my day. This morning, about 15 minutes after getting to work, a coworker came and told me my hazards were flashing. I went out to my truck and they had stopped already.

I drive about 45 miles one way to work, the truck runs great, the only other issues I have had is the 4wd started not wanting to engage in the last few weeks...unsure if they are related. The truck has 78,000 miles, and I have owned it since Oct, 2010. I have searched and searched and cannot find anyone else who has had an issue like this. Does anyone have any thoughts? I am going to test the battery when I get home, but it is only 2 years old, and has had no issues before. Any suggestions would be much appreciated. Thanks guys.

 

Do you have an aftermarket alarm?

 

Nope no aftermarket alarm, nothing at all that would cause this has been added. I'm stumped.

 

The battery is a very good place to start.
When the battery starts to go, the computer starts doing weird stuff.

 

Dumb question, Are you carrying your key fob in your pocket?
Reason I ask is I installed an aftermarket remote start on my truck and there has been a couple of times it has activated while in my pocket. I now clip my keys to my belt loop or leave them in my coat pocket.

 

I wish it was that easy lol. I have hit the lock button with the keys in my pocket before, but both of these instances the keys were hanging on a hook or on a shelf, undisturbed. The interesting part, was that I thought maybe the truck was getting errant signals to the remote lock system, so I tried locking repeatedly and unlocking repeatedly, to see if i could mimic it. However, in the unlocking case, the door lock solenoids were still very loud, and I did not hear them when the lights were malfunctioning. I know this for sure, because I Listened to it thinking my wife was inside the house hitting the button on my keys messing with me lol. It definitely, 100% was not flashing the lights because of the locks being activated.

 

Definitely check the battery.

 

I agree with this.

 

I have a 2015 Fusion with remote start from the factory. Several times I found the car running. After the first few times, I am absolutely positive the the start button was not hit. Ford is at a loss for this also. No rhyme or reason that I can figure out.

 

OK, I checked the battery voltage yesterday before I left work, with a ****ty harbor freight meter I keep int he truck. It was at 12.06V with the door open, so the running/marker lights were on. Unfortunately I didn't think to measure it without the load of the lights. I had my coworker hold the leads and watch the meter as I started the truck, it started fine, the reading dropped to 10.25, then read 14.35 once running. So, the alternator is working, the battery is not fully charged though.

I measured it again when I got home, it was at approximately 12.25V with the door open/lights on, 12.35V with the door closed, lights off, no load. I checked it again this morning with the door closed, no load, and it was 12.05. So this tells me, something is draining the battery overnight. Interestingly, this fits since yesterday was the first day I drove the truck since Friday, giving it all weekend to discharge....so maybe it is not a coincidence that the flashing lights crap happened on a Monday.

I am going to hook a charger up to the battery tonight when I get home, and see if it takes a full charge. I did pull the caps and check the fluid last night as well. All cells were full, well above the plates, but the outermost two cells were slightly lower than the rest. I could not find my hygrometer anywhere, so I might pick one up this weekend and measure the cells.

Over all, I am still not convinced the voltage was low enough to cause issues, but I suppose all I can do is wait and see what happens.

 

I’m having the same issue! I have a 2017 F150 and the hazards keep coming on more and more frequently by themselves... now the horn will go off by itself too while driving or just sitting parked and turned off! 🤦‍♂️

 

ive got the same thing going on took it into ford and all they did was unplug the horn fixed it for over a month but once the weather got really cold again it came back, also the parking brake light will flash on while driving, the rear cargo light will stay on while hazards are flashing and if i hit the cargo light button it will stop the hazards as well but they turn back on once i close a door

 

looking for help with this also, just started today. She sitting in the driveway with the battery disconnect it because the horn. Would appreciate any help. Planning on taking the battery up to a Advance Auto tomorrow after work to get tested.

 

It seems like there are different problems here than what I originally had. Mine only happened when the truck was parked and turned off. The best I could tell it was a failing door switch or hood switch, making the truck think someone opened a door after the vehicle was locked. It never happened when the truck was unlocked.

Those of you experiencing issues while driving, I have no explanation for at all. The only thing that makes sense there is a wiring harness or pcm issue. Sorry I can't be much help.

 

If the voltage drops down to 10 volts...your battery is definitely part of the problem.
A fully charged battery should read 13.2 volts or very close to that. At 12.5 volts, the battery is only 50% charged, as per this article: https://www.scubaengineer.com/docume...ing_graphs.pdf

Hook a charger up to it at around 2 amps or "trickle charge" and leave it overnight...preferably 24 hours....and see if that makes a difference. I suspect a new battery is in your future.