I have a 2006 F350 6.0. I have an upgraded 56 or 58 volt FICM. In January 2018 when the temps dropped in the teens my batteries (new) died. When they were recharged the check engine light came on and it had all the open circuit to virtually all glow plugs. I replaced the glow plug control module and it worked for several days and the check engine light came on for glow plug number 3. It was in the shop for about 2 weeks and every time they thought they had it figured out the check engine light would come back on. Even the shop went through 2 glow plug control modules. For some reason it keeps shorting out the GPCM. The truck still starts and runs good but the check engine light keeps coming on. All glow plugs were replaced and so was the glow plug harness a year ago and i never had this issue until it hit the teens and the batteries died. I just put another 2 brand new batteries in and it is the same thing. Looking for some suggestions.

 

Did your problems start after the FICM replacement or before? if after i would start there. good luck electrical problems can be annoying.
Chuck

 

The upgraded FICM was on the vehicle when I got it. I replaced the glow plugs and harness in February 2017. Did not have an issue with anything until January 2018 when the temps went to the teens. I was unsure whether the upgraded FICM had any affect on the glow plug control module.

 

found this document ef_456.pdf it covers the 6.0, the glow plug module is controlled by the PCM,
there are also common connections for each bank of glow plugs, water could be in those causing them to fault.