How can I leave a 2018 Ford F150 locked and running with full AC?

I would try a second remote to see if you can lock the doors. If not I think you are out of luck.

Usually a remote start system will allow you to start the engine and leave it run for 10 minutes or so. If you leave the air conditioning system on when you shut off the engine, exit and lock the vehicle. Then use the remote start feature to start the engine back up. The air conditioning should still be on with the vehicle still locked and running. Just don't be gone for more than 10 minutes. Hope that helps! Jim

Thank you Jim! I do exactly as you've instructed, but the AC doesn't run at full power. I have an auto off function that turns the engine off when I stop. Could that feature be keeping the AC to a minimum?

You're welcome. Glad to help. Check your owner's manual and see if the auto engine off feature can be overridden. My friend has a 2019 Ford Escape and there's a button on his dash to cancel the engine off feature for the ignition cycle. Maybe your local Ford Dealer can program the computer to give full air conditioning with the remote start feature. Hope that helps! Jim

Press the 7-8 and 9-0 on the keypad at the same time. Engine will run with full a/c until gas tank is empty.

Simple solution: don't be in a situation where you need to leave your dog in your truck.