Diagnosing improper control of glow plug relay?

[jtomasik]

My ECM doesn't seem to be turning on the glow plug relay when I first try to start my truck. After 2 or 3 attempts at starting (turn key on, wait until "wait to start" light goes out, crank for about 10 seconds, turn key off, wait for a couple of minutes, repeat). Then, after a few attempts, I'll hear the glow plug relay click, and the truck will fire immediately. It was 30 deg F last night, and the truck had this behavior this morning.

The glow plug relay, the glow plug harnesses, and all glow plugs were replaced last winter, but the hard start problem didn't disappear. Not sure if this problem was happening before.

Any ideas?

[JSchuricht]

Get out the meter and start checking the wires to the GPR. Wiggle them around when your checking to see if one is broke.