I have a 2003 ba Fairmont, car works and drives well, but when it sits overnight the next day battery is flat, if I disconnect it at the end of the day and reconnect it in the morning its still fully charged, so its not the battery, checked the alternator its not that, checked glovebox and boot light its not them staying on,
the guy I got it from said he had it put on a machine and apparently a module or something behind the stereo is draining power or leaving a circuit open? but he couldn't remember what it was called, would anyone have any ideas???

Only Module behind stereo if standard is for remote control signal receiver use ammeter In series with battery negative terminal and negative cable and check current draw don't try to start with meter in circuit .05 amp Rough figure allow time sometimes 1hr or so for all systems to shut down and check current draw hint open doors and roll locks so you can access vehicle with out restarting system shutdown cycle if excess current try pull fuses for circuits causing problems or disconnect items to locate - check multi pin plug near air box behind left headlight for moisture /corrosion common cause of flat battery..

thanks ted i will check them out.

I'm having the exact same issue, let me know what you find out. I have worked through my battery drain down fuse 9 'batt. no 1' which I believe runs the ICC and BEM. I'm not sure if something inside the ICC or BEM is stuffed or related to the alarm but mine is draining severely with this circuit running.

Big thanks to TedW for taking the time to write me some advice in terms of locating my particular issue.

I have isolated the battery drain down to fuse 28 "ICC", the battery will stay full overnight 12.3volts if I pull this fuse and goes flat overnight 11.5v or less with it in. I tried to do the amp test with the negative terminal disconnected but I couldn't replicate the battery drain. If I open and shut the doors I see 0.87amps which soon drops to 0.21 and then down to 0.02 after 15mins or so. It doesn't make a difference if I pull the fuse or not, I still see a similar amp level which has me stumped. Maybe I haven't waited long enough to do final reading so I will try again when I get a chance.

For now I am just pulling the fuse to the ICC and that is at least saving my battery. TedW suggested to see if the CD player is working and yes it all seems to be working perfectly except for the central locking button on the ICC.

0.87amps which soon drops to 0.21 and then down to 0.02 indicates no fault at this particular moment - grind the plastic off the end of a BLOWN fuse solder wires to each terminal reinsert this fuse at fuse 28 with ammeter connected across the wires tape to keep seperated will enable you to detect any change in current draw... ie.drawing power after allowing system to shutdown without disconnecting battery.....for protection of circuit add good fuse in series with one of the wires....

TedW

I did what you suggested Ted, it's reading a constant 0.39amps across fuse 28 and I'm guessing that would enough to drain the battery. For now I am wiring a switch across fuse 28 so I can switch the ICC on and off without having to pull a fuse. Thanks again for your help.