I had my truck up on my lift to change the oil and when I lowered my spare to check the air, I noticed a module of some kind that is bolted on the cross member directly above and to the left of the spare tire. There are 2 cracks on the plastic case, and the lower crack is even into the aluminum housing that bolts to the truck. I cleaned it good and put some silicone sealant over the cracks to try and prevent any water or dirt from entering. Who knows how long its been like this and if there isnt already dirt, water and corrosion reaking havoc on the insides? So what is this thing and what does it do? Should I replace it?
Fuel Pump driver module. The are notorious for cracking, breaking, leaking and shutting off power to your fuel pump. If yours has been cracked for a while i would think about replacing it sometime before it leaves you stranded. Just take that part number on the sticker that is visable in the one pic and go to the dealership and get a new one.
That is the "Fuel Pump Driver Module" as stated, it is an aluminum housing with pastic cover bolted to the frame and when you remove it, you may find the whole rear of the housing where the aluminum was in contact with the frame corroded away. I've seen some so bad you could see the electronic guts potted inside. They will leave you stranded if they fail.
Yours is already broken. You will see when you pull it off that the surface to which it is bolted is not "flat". Tightening the bolts is likely what broke yours.
When you get the new one, Ford also has a kit designed to space the FPDM off the frame rail so a 1/4" or so gap is behind it so no contact between steel frame and aluminum housing. Use the kit or devise your own method.
I read a thread on the subject last year and checked mine and found corosion started. I cleaned it, clear coated it heavily, and got some longer metric bolts that fit the threaded holes, cut the heads off to make long studs, locktited the studs in the frame holes and used a nut to tighten up. Then I placed washers on those nuts and the FPDM and another pair of washers and secured with nylock nuts avoiding overtightening.
When first looked at FPDM
Corrosion just starting
Cleaned and clearcoated heavily
Back in place ... also had cleaned and throwed some paint on the frame part
Mine is unplugged in last pic, I had to repair a wire I found almost chewed through, no doubt by a darn squirrel. I also threw a couple zip ties on there buit I really don't think there's much chance of the nylock nuts loosening up, just a moment of "redundent overload" I guess.
Thanks guys for all the info. I will probably just replace it soon. I'll give the dealer a call tomorrow to see how much an OEM one will cost. I know dorman makes one but I am always wary about buying aftermarket electrical parts especially if it is a china special.
I ended up ordering a doorman unit from rock auto. 66 bucks with shipping. I installed it today and all seems well. The new one came with rubber bushings to isolate it from the frame rail. The case was so corroded that there was almost a hole in it on the back.