About two weeks ago, I became the new owner of a 2008 Buick Lucerne CX. The information, in this thread, probably saved me a towing bill, somewhere down the road. With that in mind, I ordered a fuse box off of eBay, swapped it out, then kept the original as a spare. Since I just swapped fuse boxes on my car, I wanted to post this, before I forget all of the details.
As mentioned earlier, the fuse box itself clips on to a plastic piece, which is attached to the bottom of the trunk.
This bottom piece is held down by 3 nuts. While you don't have to remove it, doing so makes it a little easier to maneuver the wire connector blocks around. Used two flathead screwdrivers to release the first two clips. The rest were fairly easy, after that.
Then came the task of releasing the wiring connectors. On mine there were two connectors that each had a single wire, plus the 3 large wiring blocks. The first two didn't come out as easy as I thought they would. Finally ended up grabbing each of them with a large pliers, while holding a screwdriver in the other hand to release the clip. For the 3 large connector blocks I used a nut driver on the three bolts. They're captive bolts and loosening them actually releases the connector blocks, most of the way. As mentioned above, there are tiny tabs that need to be released when removing the large connector blocks. They're hard to see, but you can tell where they are by rocking the connector block back and forth. Used a small flathead screw driver to release them.
After this, it's just a matter of swapping fuse boxes and putting everything back together. I found that it's a lot easier to put this back together than it was to take it apart.
The fuse box that I purchased came with fuses and relays already installed. The fuel pump relay was the older-style tall relay. As insurance against future problems, I replaced it with the newer-style relay...the one mentioned in TSB "15-NA-051: No Start Condition - Seat Bracket Contacting Rear Electrical Center". The part number, mentioned in the TSB, is 88953222. I found it on Rock Auto listed under part number: D1755A. They're basically two different part numbers for the same thing. The AC Delco bag that the relay comes in actually lists both part numbers on it.
The eBay fuse box actually had a couple less fuses than the original. I didn't transfer any over since there were no electrical contacts in the slots for the "missing" fuses. Was a little worried about that, but when I took the car for a test-drive, I didn't notice any problems.
In the TSB, they actually recommend cutting 5mm off of the seat bracket on the driver's side:
Cause
The rear seat bottom frame may come into contact with the rear electrical center (REC) cover. The contact/interface results in varying amounts of
deflection of the fuel pump relay (FPR). The movement of the FPR causes potential wear of the male terminals on the FPR.
Correction
^ Install a low profile fuel pump relay.
^ Remove material from the rear seat bottom frame, driver side mounting brackets.
6. With the rear seat cushion on a bench, measure 5mm (0.197 in) from each edge of the right side seat mount bracket and mark with a paint marker as
shown (1).
7. Using a cut off wheel or equivalent, carefully cut each side of the bracket as shown (1).
Haven't cut the seat bracket, yet. That'll be a project for another day.