One flash indicates that the remote start system is disabled. You have to ask yourself whether you want to use the remote start or whether you want to insist that it work the way you expect it to work. Reset the remote start by getting into the truck and starting it. It appears to be the case that some other members and I experience a similar situation and that is that the truck very often does not recognize (or count) the very first press of the remote start. About the only way to counter the problem is to slow down. Press once, break, press second time - and if you pace it right and the truck has counted "two," then you will see two flashes of the lights and it will start. Keeping with the pace or cadence of the first two presses and there are no light flashes, press one more time to see if, perhaps, the truck recognized only one of the first two presses. It happens to me a lot. If the truck recognized one of the first two presses and you press twice, it will definitely cancel the remote start. I also suspect that it will make the system disable itself, but that remains a guess. If the one more press is recognized by the truck as the second press, you'll get the two flashes and start. However, any time you are seeing one flash of the lights, you can be reasonably sure that the system is disabled.