Question about Glow Plug Monitor Error P1395

[dgale914]

I have an error P1395, which I just found out is a "Glow Plug Monitor (Bank 1)" error. I just recently replaced the glow plugs and glow plug relay, so I was surprised to see this.

Anyway, I've tried to clear the code but it immediately re-generates the same code. My question is... where is this 'glow plug monitor'? Is it an electrical device somewhere in the engine compartment?

Any help figuring this out would be appreciated! It's in a 97 PS HD 4x4.

Doug