I started the truck today getting it out of storage from inside in my shop. It died after 15 seconds but its been sitting for a few months with a maintainer on the batteries. Fired it right back up AFTER the wait to start light went out, it ran great about 45 minutes or a hour and took it through a car wash and then rolled over to the pump to fill the tank. When i went to start it back up i didn't notice the wait to start light and then had the service engine soon. Ran fine going home. Got home and pulled the code P0381. I did not notice a wts light when I did this, thought maybe the bulb burnt out. I let the truck cool down and WTS light lit up but seemed shorter than normal, truck fired and service light came back on as soon as WTS went off. I didn't see any codes for individual glow plugs only one code the P0381. I have the original module on it but around 15 years or so i had to swap the module connectors s and used a kit intended for a 6.0. all wiring still looks good where I had tide it up. Anyone else go through this with a control module on a Excursion? Engine was hot when i fired it back up at the station, would not have thought the glow plug circuit would have been in play at that time. Kinda hate to just throw a new module at it. Seems weird it been in a dry shop out of the weather for several months , in fact i left it sitting on my lift after i changed the oil.i also didn't notice any water around the power distribution box or any dripping on drivers floor mat. Been through that around 2014 with the windshield leak and installed a new fuse box.

 

Well not sure what i did. I went ahead and ordered a new Ford glow Plug controller last night. Afterwrds i got to thinking, maybe i have a faulty battery as when it started to cranki is when it threw the code.. Isolated both batteries and they were sitting at 12.6 without a overnight maintainer and passed a digital load test. I cleaned up the connections anyway. they werent really bad , just a little dirty on top as i use corrosion xhd on the posts after i get them toghtened down. Got in and the WTS light lit , i waited until it went out and it fired right up with no SES light. Put my P3 brake controller in troubleshooting mode and it sat there at 11.8 volts for what seemed like eternity and then ramped on up to 14.6..All seems good and its colder today then yesteday..

 

Sounds like the fix was cleaning the connections. Sweet!

The WTS light illuminates independently of the glow plugs being on. They can be on for up to 2 minutes depending on several factors but mostly temps.

The voltage of 11.8 sounds about right for when the glow plugs are sucking juice, and once they turn off the voltage popped up to normal.

 

Glad you got it working...I guess you'll have a GPCM on hand and ready for when you need one.