The heater relay in 05 silverado's are known by Chevrolet as failing, the fan switch with the numbers 5 went out full boar had it fixed now

1-4 went out and it is the relay again. gadd

On a cold morning, started up the truck turned on the heat. And noticed the fan would not work in the 5 position. Positions 1-4 worked perfectly. Chevy said it was a bad relay switch. Had it repaired by Chevy for about 200 bucks! It has worked every since but it would have worked fine without it. Fan blows plenty hard in the 4 position. If it breaks again, I won't be repairing it.