RockAuto were true to their word and FedEx delivered a package to me this afternoon containing a Motorcraft glow plug control module and glow plug solenoid. Order placed on Wednesday afternoon, parts received Friday afternoon and installed late Friday afternoon followed by a 20 mile test drive. Ford has changed the mounting plate and dimensions of the glow plug solenoid so I had to modify the existing bracket in the engine compartment which took more time than actually swapping out the two components.
No check engine light coming on, no codes showing up in the DP-Tuner tuner and the truck is running like a top. It sure feels good to have this F-250 back on the road. Looking forward to the new windshield on Tuesday, and I'm going to give the cab a good vacuuming and cleaning this weekend. I'll try starting the truck tomorrow morning without plugging in the block heater and see how it does. The check engine light was coming on with the key turned on but before engaging the starter, which convinced me that the glow plug control module and/or the glow plug solenoid had failed.
There appears to be a heating element in the intake that's connected to the solenoid, so in addition to energizing the glow plugs, the solenoid also enables current to flow to the heating element. It's no wonder that the truck has been so hard to start on cold days when it's not plugged into the block heater. It feels good to get this resolved myself and for little cost. I enjoy having a project vehicle to tinker with but also one that requires no work. This truck has been awesome, and to think that it's 23 years old and still an excellent vehicle. I hope I can keep it running for many years to come.
My neighbors 2019 Duramax has a glow plug problem too so he's not doing too well with the blown head gasket on his 2005 or so Duramax and now his "new" truck.