I have discovered the source of several electrical issues has been the corosion on the inside terminals of my primary fuse relay box, under the hood. Has any of you encountered this and futhermore did you replace the box? Ford no longer offers the part for the 1998 F150, 4.6. Even if they did, it would be over $800. I am stumped.

 

It's not that unusual to get corrosion in there, depending on where you live and how well the fuse box is sealed up. If the corrosion is not too bad and the connections are not shorted out or melted, you can clean it out and that should take care of it. Unhook the battery and pull the fuses/relays one at a time (or take a pic and you can pull them all out without worrying about putting everything back correctly) and spray some WD-40 and clean out the connections with small pieces of sandpaper, nail file, ect. Then let it dry and/or blow it out with some compressed air. Use some dielectic grease when you replace the fuses and you can also put some silicon on the fuse box cover and a big zip tie to keep the cover tight. If the fuse box is fried, you might get lucky and find a good one at a junk yard. Good luck with it, and welcome to FTE!

 

To add to that...WD-40 works well,but it has some tendencies to dry up...I use Dielectric grease..This is the same stuff used on spark plug boots etc. It can be found at almost any A/P store.The grease I use is Dow-Corning "compound 4".We have an abundance at the shop,and it stays where its supposed to.....

 

Get a can of contact cleaner and spray all of the connections one at a time as you pull and replace the fuses. WD-40 is not a true cleaner. The WD stands for water displacement. The grease is a good idea but in moderation.

 

Water Displacement (WD-40): corrosion is usually caused by moisture.

The WD-40 would be to loosen up the crusty stuff and get any remaining moisture out of there, the real cleaning would be with the sandpaper,file, ect. The dielectric grease helps keep the moisture out once it's clean.

 

The more I dig into this box the more severe the findings. Two of the hot legs were burned off and most had green corosion on them. I ended up running some jumper wires in order to give voltage to two relays. I think it is time to search my local salvage yards.