Electrical help - 220mA drain - almost figured out!
 

So, as the title says:

1) I have a drain that seems to kill a battery in about 10 days of sitting with no driving.
2) Measured on a DMM, the current drain when the car is off is ~220mA total
3) At the very least, 210mA is being drawn on a White/Blue wire coming off of the X-07 connector in the engine bay.

After I pulled all of the fuses, the current draw was still there. I started pulling connectors, and 30 seconds into it, I found this one. When I separated the two halfs of X-07, the car's current draw dropped to ~10mA, as I didnt want to change the range/test lead position.

I started jumping wires between the female and male ends of X-07 and discovered that the white/blue wire was carrying the current. I then hooked X-07 backed together, and cut the white/blue wire on the front harness side or female side (im pretty sure anyway that its whats called the front side). Sure enough, current draw dropped to near 0A.

All I can see that this wire supports is the ABS function. If its tyring to send a signal somewhere, any clue what the signal is?

This car was originally an 88 (convertable) and has a 91 JSpec turbo swapped in.

When you stated you pulled the fuses did this include the engine bay fuses as well which are located by the leading coil? There is a fuse in the main fuse box that is for the ABS system. If you pulled this fuse wouldn't it stop your amperage drain if the wire in question only served the ABS?

you'd think so... but the reason i even mentioned the engine swap and whatnot is because this may have been someone's "custom" lol... work.

yes... i pulled the fuses in the engine bay as well... the only one that killed the draw was taking the cable off of the MAIN fuse

I'm guessing you are referring to the cable that leads to the engine fuse box from the battery to supply voltage to this fuse box as opposed to the one that comes off the engine fuse box.

thats a negative ghost rider...

The current dropped when I pulled the cable off of the ass-end (after the fuse) of the fuse box... not that it would matter, as the fuse is still good.

Not sure of the difference but on an S4 the Black wire that comes off the engine fuse box travels to the ignition switch and to the two circuit breaker fuses in the interior fuse box only. Does the S5 wiring diagram show differently? Also, do you have a link to an S5 wiring schematic which doesn't take all day to download as I can bring up an S4 diagram in a snap of a finger but can't say the same with respect to the S5 version.

enjoy... this is the one i was using.

http://www.rotaryart.uk.com/acatalog...5wiringLHD.pdf

Going back to something you mentioned earlier and that is if you pulled the Main fuse you would still have voltage on the Black wire that comes off of (ass end) the engine fuse box.

This link has the same download speed as the one I was trying to access earlier. Could you perhaps post the relevant pics of wiring diagram. If not, I'll have to wait til perhaps tomorrow to wait to download the S5 version and print off the necessary material.

EDIT: One other thing and that is when you tested for amperage drain was this done right after you had the car running or had the car been sitting for a period of time as the electrical circuits in the car take a fairly long time to power down when the ignition is turned to off.

i didnt know you could pull the main fuse....

all i did was connect my dmm (in series, duh) between the negative battery cable, and the negative terminal.

Next I started pulling fuses. i pulled all of the ones in the engine bay (minus the main), no luck. then i moved on to the cabin fuses... again, no luck.

finally i went back to the engine bay fuse box, and pulled the black cable off of the aft end of the fuse box, the black cable on the forward end remained attached. (i dont know what all this black cable powers, but apparently that white/blue wire runs to it somewhere).

You can remove the main fuse but it is screwed in underneath the fuse box so once the screws are removed it will pull out. When it is pulled there should not be any voltage present at all on the Black wire that it feeds.

When you did pull fuses did you also include the 30 amp circuit breaker fuses in the interior fuse box. I understand there are some wiring differences between S4/S5 but w/o even having to look at the wiring diagram I am sure this Black cable only feeds three items if you count the two circuit breaker fuses as two separate items.

If you look alongside the steering column just underneath the dash on the side closest to the driver's door there you will find the plugs to the ignition switch. One of these plugs houses a B/W wire as well as the "Black" wire that comes from the engine fuse box. Disconnect this plug briefly and see if your amperage drain disappears or not.

disconnected the black one... no change in current draw.

The W/L wire connects to the alternator(not ABS) on the backside via a two wire plug. . Disconnect this two wire plug and see if the drain disappears. The alternator on an S4 does not drain voltage from the battery when the car is not in use, but I think it slowly does on an S5. You need the W/L wire to run your alternator properly.

the alternator was my first thought... my second thought was that 220mA was a helluva lot of current for it to pull while off.

Well... I cut the wire. As long as my alternator spits out the additional 2.4 volts, I think thats all I need to be concerned with (though I'm probably wrong).

What do you mean by "spits out the additional 2.4 volts." Do you mean w/the wire cut that the alternator is producing 2.4 volts more than it had been providing?

No, I mean that as long as I'm seeing 14.4 volts on the battery while the car is running, which is something that I'll go check in about 5 minutes, then whatever the W/L wire does for me is something I may not need to worry about. Nobody knows what it does?

Eh... i just looked at the wiring diagrams again... my vote remains that it is a part of the ABS system. :(

The W/B wire in the plug that connects to the alternator does connect to the ABS system but not W/L. If you look at the diagram that depicts the alternator it would show this to be the case.

voltage at the battery is 15.4 btw, havent check it with that wire re-connected yet

I think I understand what you mean by the term ABS. ABS is an acronym for "Anti Lock Brake System" while I think you are using the term to represent the "AIr Bag System," and this has led to the confusion. With respect to the Air Bag System the W/L wire does connect to it but it does it before connector X-07 via A-06 and again, this occurs before X-07 so if the drain is occuring after X-07 then the Air Bag System is not a player in your problem at all.

Now the voltage output you are getting at the battery is off the charts to say the least as it should max out at 12.6 volts. Not sure if you checked this voltage reading w/the car running or not but I am going to guess you checked it with the car running. Either way this is too much and you are going to seriously damage your electrical circuits one after the other and the root cause is likely the W/L wire being disconnected from the alternator as the voltage regulator will cease to function with it disconnected and it will be goodnight to your electrical system. If you think you have problems now just wait.

i meant the voltage at the battery when the car is running... sorry.

so we're saying the the w/L wire involves the Vreg on the alternator?

u using a na main harness and a t2 emmission harness??
info
http://forum.teamfc3s.org/showthread.php?t=44789

this is what i took out of that somewhere:

So now lets look at the S5 set up...

Now you have those same battery, run, and ignition/voltage reference leads...

The Battery is the big wire running to the 100amp fuse

then the two smaller leads
The voltage reference lead, (white/blue) running to the EGI fuse and powering the system.

and finally the run lead (white/black) running to the warning/clock panel, and the ABS (if equipped).

Now what happens if you mix those two up??? You back feed the ignition system through the clock/warning panel and you have a current draw.

Sure the system will charge the battery and the alt will put out sufficent voltage, with the run and ignition/voltage reference leads mixed up (after all the other side of the clock/warning or CPU both are voltage with the key on), but you are not shutting off the voltage to the alt if you have the two mixed up.

Maybe you can't tell what wire is what in the car and are worried about blowing something up...

Okay... on a S4 car unplug the CPU. Turn the key on (but don't start the car). The small lead at the alt with 12v+ on it is the ignition reference lead.

On a S5 a little different. On a S5 pull the EGI fuse from under the hood. Now turn the key on (but don't start the car) the Ignition reference lead is the one that does not have voltage.

Maybe you guys are missing how an alt with an internal regulator works???

Okay, you have the big battery lead... this the output of the alt. The internal regulator looks at the difference between this output and the reference input. So if it sees the voltage on the reference lead is only 12 volts, but it also knows that the voltage on the output is at 14 volts, it continues to increase the output voltage until the reference wire is within .5 volts of the output.