I have a Chevrolet Silverado 3500 1 ton diesel truck. The truck will periodically burn out glow plugs. I have changed glows multiple times and used different types. I have changed the glow plug controller and the coolant temperature switch with no change. I have checked all fuses and they are good. Checked voltage and the correct voltage is present. Does anyone have an idea why this is happening?
First off, I’m not a domestic diesel guy so take anything I say with a grain of salt, or two. 
My experience has been with foreign car diesels (mostly VW) and in the case of VWs a faulty glow plug was often due to a faulty injector or injector spray pattern.
With multiple glow plug failures (assuming it’s more than one a a time) maybe something to do with injector pump timing. As I said, I’m not a domestic guy so I may be shooting from the hip on a Chevrolet. It’s something for consideration anyway.
Don’t think it’s the timing or the fuel injectors. Trucks gets around 21 mpg. I think it would get much worse if that was the case. But thanks for sending the idea
It’s true, a worn, poorly atomizing injector can cause glow plugs to burn, yet atomize fuel well enough so that the fuel will burn to produce normal power, not affecting mileage. Can you identify cylinders that burn out plugs the most and least and exchange injectors to see if the problem moves too? Are you using a known good quality glow plug brand? Bosch Duraterms can better withstand more continuous glow time than some others. You could wire in a temporary 12 volt indicator light to verify your glow plug on time.
Is it ALL the plugs failing or just the same one or two that fail?