What's this thing do...?

[HammerDown]

Red X charging system?
Also, which wire on that solenoid goes to the GP controller?

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[Jake S.]

voltage reg-u-ma-later.

 

[icanfixall]

Thats what it is... Your type of alternater doesn't have an internal voltage regulater... So Ford put it out there. Sometimes they burn up when you don't pull the battery cables (either +or -) when you try to replace them... Happened to me twice before the electric shop told me to kill the power... Never had the problem again... Now with my serpentine belt system my alt has the internal voltage regulater... Much easier to deal with... Make sure this reg case is firmly mounted and grounded. Otherwise it wont work... Another issue I found out the hard way.....

 

[Agnem]

Sorry Ray. I misunderstood that you had deemed it part of the glow plug system and couldn't for the life of me imagine it.

 

[Willie Two]

Fusible link

Is Hammerdown not also asking about the fusible link that feeds the glow plug relay, I am not sure about his year of truck but that link is "probably" the orange one in the photo.

 

[jtate]

Sometimes they burn up when you don't pull the battery cables (either +or -) when you try to replace them...

and they will shock the snot out of you too, thats what mine did.