My girlfriend's 2002 STS has had several intermittent electrical faults since she bought the car (used) six months ago. Otherwise, it's a fine car. Being an electrical person, I didn't worry since the car is still under warranty, but I was curious how it could continue to develop so many new faults. The battery died this weekend, so I decided to do a little look-see for myself before it went back in to the shop for --you guessed it, another flaky electrical problem. I suspected a loose battery connection. The battery relay positive connection was tight, so I pulled up the back seat to check the battery. Underneath was a light film that looked like sand. There wasn't any obvious corrosion on the terminals. When I twisted the positive terminal, it broke right off the battery! Looking straight down, I could see pavement beneath the battery! Turns out, the battery had been slowly leaking acid, and the sandy residue was what used to be the floorpan under the battery.
My next-door neighbor dates the local Cadillac service manager, and luckily he was over there. Before I even finished telling him what the symptoms were, he smiled and said, "Battery eat through the floorpan?" He's seen this many times, and says there's a TSB out regarding the problem with a kit to repair the floorpan and replace the battery cable to the engine compartment.
--About a 5-day job and $1100 if out of warranty.

Forewarned is forearmed. Pull your rear seat up and inspect the area under the battery for any signs of corrosion --especially if you're getting close to the end of the warranty expiration. Check the battery terminals where the screw attaches to the battery case for any sulfuric acid seepage where the case and threaded insert for the screw mate.

I did a little TSB reasearch and here's what I came up with--
TSB#: 04-08-61-001 Feb 2004 "Body- Floor Pan Corrosion in Battery Compartment".

What a drag!!


I've had several battery failures, mostly Die Hards, in other vehicles, with acid leakage from a battery terminal.

Please stay vigilant as to strange puddles of fluid under your vehicle. These are very evident if your car is garage kept -- if you keep your eyes open. Sulphuric acid can do a lot of damage!

Always try to maintain a 'curve' as your cables connect to your battery; this allows some flex of the cables to reduce road shock transmitted to the battery terminals.

WOW just went through this problem with my STS 2001. Car was in storage for a few months, went to start and dead battery. Went to jump start and the positive cable fell off in my hand and acid started leaking. THANK GOD for extended warranty called them up and had my car towed and they installed a new battery only! nothing about the battery cable replacement 1100 dollar issue thow. I did see from day one of my car, it is always charging the battery at 14.8 to 15.4 all the time. I wonder if this is normal ? But thanks for the info on the
TSB#: 04-08-61-001 Feb 2004 "Body- Floor Pan Corrosion in Battery Compartment".

Charging the battery at 14.8 to 15.4 is a bit on a high side for my taste. I'll preffer 13.5V. Overcharging leads to extra corrosion and make battery' life shorter.