1994 F350 7.3L Non-Turbo Navistar or International glow plugs won't heat up. I am asking this for my uncle who does not have internet access. I will be as specific as possible.
He has checked all of the glow plugs, and they are fine. The soelenoid for the glow pugs just clicks. He has replaced that soelenoid, still clicks. Someone told him that there is a cooling sensor of some sort that might be telling the system that the engine is already warm, preventing the glow plugs from heating up.
Any ideas? All help is greatly appreciated. Thank you.

peterson570(No Email Addresses In Posts!)