Good Morning -
I noticed today my heater did not kick in when I started my truck and about 10 minutes into my drive I finally began feeling hot air. Soon after the air was no longer blowing hot. Any thoughts on what this may be and how to verify the issue? I'm interested in taking care of this myself if it is easy/moderate level of difficulty to isolate issue and fix. Thank you

 

Are you saying that the blower was working the whole time, but there is a lack of heat from the vents? Have you verified your coolant level? Just starting with the basics. Low coolant can cause a lack of flow through the heater. Are both heater hoses going to the firewall getting hot?

 

My guess is you possibly have a blend door actuator that's getting ready to take a dump. You might want to be considering an extended warranty in a hurry. I had one on my 2011. I had the driver's side actuator go out. It saved me almost $800.