I have an 01 S40 with a peculiar battery drain. Brand new battery. Alternator charging very well. Wait 2 days. Try to turn over and dead.

I noticed that if I have my hazard switch depressed that my blinkers will not work, nor will my lights.
Once I press the hazards switch (to the on position) then my blinkers and lights will work.

Something has me thinking that this could be the cause of the matter but I'd like to get a quick additional thought if possible.
What else should I check before disconnecting the hazard switch.

Thanks in advance!

 

That's an odd failure - not sure that has anything to do with your battery drain issue though. Now if it was lighting up some lights constantly... maybe.

Otherwise I'd recommend disconnecting the negative terminal from your battery and inserting an ammeter in between the negative battery terminal and the cable. You should measure only a small fraction of an amp of current with the doors closed (opening the doors turns on the dome lights, and activates other things). I don't recall the exact drain that's "normal" but it's tiny, and if you're running down a new, charged battery in two days, I'm sure you'll see the current (I'd guess it's at least a few tenths of an amp, if not more than an amp).

Once you do this, AND make sure the doors are shut, then it's just a matter of pulling fuses until you pull one that drops the current drain dramatically. Yes, you'll have to have the door(s) open to get to some of the fuses, but you can turn the dome lights off, and just factor in the added current that is flowing because of the open door (so if you have 0.5A flowing with the doors shut, and 0.8A with them open, know that your "resting current" will drop by 0.3A when you shut the door AND have pulled the "right fuse".

Once you've ID'd the right fuse, it's just a matter of figuring out what circuits that fuse powers, and disconnecting / measuring the suspected items.

 

 

I don't think the 01 S40s had the satellite radio option. I'd also recommend habbyguy's approach to isolate the circuit path at fault. Then you can look at the wiring diagrams to see what devices are in that path - ie the CEM (which has internal relays) or a specific plug in relay. You can also pull the plug in relays to see if those are energized when the key is off. The good news is if it turns out to be the CEM, you can simply swap out a replacement as the Gen1 S40s are not paired to the computer.

 

 

Wellp. This is solved...my kid turned on a light in the back I never noticed because I always worked on the car in daylight. now I have other issues with my alternator.

 

what kind of other issues on the alternator? Check connections to the battery and ground and inspect the cables/wiring harness before you suspect a bad alternator. Some of the big autoparts stores will also test the charging system for you (ie battery, alternator output) - but quite often its a battery connection.