Not entirely certain why but the remote start button on the keyfob doesn't start the truck. I just get a solid red light on the fob for a few seconds.

Any idea how to fix this? Lock, unlock and tailgate drop work fine, and I can remote start from the app without issue

 

Has it been working before?
Do you know how to use it? Have you read the owners manual for proper function?
What year is your truck, it may not function the same as the instructions for my 2016.

Your must do this:
lock
remote start
remote start

It literally takes all 3 presses.
The red light on your FOB suggests you are not using the lock button first.
Red means it received a signal but cannot carry out the function (I think).

 

weak batteries will do this too when trying to perform a 2 way function (remote start). there isn't enough power to carry the 3 button presses and listen for the return signal.

 

Yup. Likely another "manual?".

 

Flashing green = remote start in progress
Solid green = successful start
Flashing red = remote start not successful
Solid red = Successful shut down or response not received

Either your truck is no longer responding to remote commands, or it is not receiving them, either way, it's not responding. New battery is always the first step when the vehicle isn't responding.

 

Is it possible that the FOB battery is too weak to send a remote start signal but not so low that the dash hasn't alerted driver of low battery level in the FOB?

Not saying my example is perfect, but shortly after taking ownership of my used 2016 I was alerted that the FOB battery was low. To that point in time all buttons functioned as they should, even after the alert was displayed on the dash did things still function as normal.

Also, I see OP has a signature -not sure if that was there this morning when I first asked what year.
I scrolled down after starting my post to see if info was posted but signatures do not display at that point. Apologies for asking what year if ti was already posted in the signature.

 

I’m an idiot folks. Wrong button sequence. Guess I should have read the manual

 

Great, time for a closed thread.

LOL

 

Hey don't beat yourself up, we're all guilty of "operator error".

 

NO! We must discuss the merits of RTFM'ing!!!