dash lights flashing/horn blowing on F250

Very simple answer......................it's a Ford!

Out of left field I know, but is there a possibility of mice/rats or even Singapore ants getting to the wiring. They can cause much damage.

My MIL had issues similar to yours with her vehicle and inspection found chewed wiring.

Disco.

Hi Sue and Shaun firstly forget the clown who commented on your vehicle,you have a real truck not a toy truck.your problem sounds like you have issues with the alarm system,take it to an auto electrician and they will scan the truck takes a few minutes. Do yourself a favor and buy a scangauge and carry it with you and if you have any problems which you wont because you have a REAL TRUCK LOL you can plug into the computer and it will tell you of any issues.
I have had my EFY for 4 years and never had a flat tyre and it tows 25ft 4 ton caravan.
Cheers
Humpback

Hey Phil your wife changed it say no more LMAO dont loose her.
Cheers
Humpack

Vehicle alarm also came to mind. Does the vehicle use the horn as the theft alarm or does it have it's own dedicated siren.

Before taking it to be looked at, how about doing two simple things. First of all make sure something is not moving in the vehicle cab, an example being a cushion or backrest falling down or vermin in the cab. The second thing would be to try a hard reboot by disconnecting the battery for a few minutes and resetting the ecm.

Best of luck.

hi folks; I had the same problem some time past. Seems my movement sensor alarm system was being activated by a moth that liked to fly laps of the vehicle while it was locked. Try a good squirt of bug spray overnight; - worked for me.

I have done this several times in my F250

I was the culprit by pocket pushing the red alarm button on the remote locking device.
It is activated very easily in the pocket.
I now make sure the other keys on the key ring are pushed to the back of the fob when I put it in my pocket.
Happened three times before I worked out what was happening
Of course if you have not got a remote entry fob disregard what I have said.