Need some diagnosis advice.

[Erik Jenkinson]

I am hearing a sound that I believe to be my glow plug relay failing, but am unsure. When I start my m1009, every once in a while, I hear a continuous clicking, like the sound of the gpr, only so rapid it almost sounds like a grind. It comes from that area. I have done the Doghead mod. I also have bypassed the resistor, and have a momentary push button installed. My control card is still functional, and intact. I noticed that my volt meter was just slightly low as this problem occours, then comes back to normal with rpm, which stops the clicking. Any thoughts or advice?

 

[mistaken1]

Once you get the truck started disconnect the power wire (pink/black) from the GPR coil to see if that stops the noise.

I could be one of the other relays under the dash doing that as well.

 

[SGT Estum]

I had a similar sound to what I think you're describing. One way to confirm it is the glow plug relay would be to leave the hood open and just have someone put a finger on the GPR (obviously not on the electrical contacts, but maybe on the circular end or something). If the sound is originating from that, you should be able to confirm by touch.

As preventative maintenance, I just went ahead and replaced mine. It was $40-50 at O'Reilly's. You can search the forum and find the part number.