My turn signal indicator in the instrument cluster started flashing fast today for no apparent reason. All turn signals are flashing at the correct speed but the indicator is flashing fast. To make it even stranger, it will correct itself if the truck is turned off but acc mode is on but as soon as the vehicle is started, it starts flashing fast again.

Anyone ever experienced this or have any ideas as to what is wrong?

Truck is a 2017 F250 Platinum (all LED) with stock lighting.

 

Very weird indeed.

Do you use FordPass on your phone and if so, are there any vehicle alerts?

 

Get the dealer to check for codes and issues. Either you have a circuit or a bulb faulty, or your having plug issues with moisture, or module issues. Really get the dealer to figure it out if you have warranty.

 

Did you try sprinkling holy water on it yet?

 

Usually if a blinker going in hyper mode there is a bulb burned out, its meant to let the driver know about it!

 

Bulb out. Edited

 

I plan on letting the dealer figure this one out. All of the turn signals flash at the normal rate so none are out. The instrument cluster is the only thing that is flashing fast. The harness at the rear is still packed with dielectric grease.

The dealership did replace the left headlight a couple of weeks ago due to peeling UV coating and there was a DTC for the high beam. I cleared the codes hoping that would fix it but it’s still screwed up.

 

Yup. Check the plug in the harness in the spare tire area. Pop it apart, clean and pack with dielectric grease. I had all kinds of weird stuff happening with my 2017 last year due to that plug.

 

Weird
This just started occurring on my new 2019 I’ve have 2 months.
1800 miles
Blinkers all appear to be working correctly on the truck.
just the left turn signal indicator on the dash blinks at a high rate.
Right indicator acts normal.
Now I did have a canopy installed a month ago and that’s where my first suspicions point although everything has been working normal till today.
I’m just starting my investigation

 

I just unplugged the canopy and nothing changed

 

I found the culprit for mine so it might be worth looking into.

My left headlight was replaced before mine starting doing it and while they were in there, they changed my full brightness DRL setting back to stock. I decided to look into the settings in Forscan.

I found the As Built data using my VIN and decided to compare. The values for “fog lights with high beam LED and some halogen” and “remember fog lights and high beams on startup” were screwed up.

I didn’t change either of those values prior to the dealership visit so I can only assume that while they were reprogramming stuff, those values got changed. Once I changed those back to the As Built values, the turn signal indicator started working as it’s supposed to.

 

Thats great you found the culprit.
I’ve only had my truck 2 months and never been back to the dealer.
Never hooked up Forscan.
When it stops raining I’ll check out the trailer plugs as someone else suggested
Thanks!

 

I suggest disconnecting your negative terminal on your battery. See if it’ll reset some module/computer on the truck. I had the same issue yesterday when I was doing some wiring for my rear strip lights.

i disconnected my negative terminal on the battery and the blinker reset on it’s regular speed.

 

I had a very similar problem on 2020, left inner indicator flashed fast but the exterior bulbs flashed fine, turned out to be a bad brake light bulb.

 

It's not meant, it's reality. Bulb burned out, less resistance, power travels faster.