Originally Posted by
edcross1608
My 2005 coupe also has a parasitic drain. Here are my finding after digging into it this morning: With the car locked the drain was significant and fluctuating. In unlocked state the draw settled down to .25 Amp with all fuses in place. After checking all fuses I found Fuse #35 (instrument cluster) accounted for .05amp drain and #9 (int lights, horn, alarm) accounted for .17amp drain. Remembering that the RCM had been updated allowing the horn to work independently I'm removing fuse #9 to reduce the draw to .08amp, when unlocked. I did not check the draw by locking manually. Not ideal but an improvement
Fuse #9 also includes your alarm siren, which is the number one draw in these cars if it hasn't been removed or replaced.
The internal batteries in the siren leak over time and short out the internal circuit board causing a draw.
Here's a post I did on how to replace the alarm sirens and clean the drains. It's in 2 parts due to picture limitations:
LINK Alarm Siren replacement & Drain cleaning Part 1
LINK Alarm Siren replacement & Drain cleaning Part 2