Can anyone tell me what this wire set is for? I have a 5-6 day battery drain on a 2003 I just bought (still keeping my dying 04 i've had for 12 years for donor parts).

I can hear a constant electrical noise way after the car has gone to sleep but it stops when I unplug this from the box next to the battery.

 

did you google that A172 part number ?

 

Yes, (ie. now lol) but looks like its a large wiring loom and not specified what it goes to as its just old ebay used parts. I can't imagine that it's meant to be constantly humming though. So might have to resort to pulling individual fuses... Or... Just never leave it stationary for 4-5 days. But i appreciate its not good for the battery to be constantly draining.

 

Does it plug to the left, middle or right module ? ( assuming that on RHD cars, the right ( viewed from the front ) module has the fuses on it.

 

Maybe a wider photo helps. It hooks into the side of the boxing. Separate from everything else

 

I think one of those wires feeds the A/C clutch. Forgotten which one, but you can find it in the wiring diagrams in the service manual.

 

That is connector C106.
You need the wiring diagram documentation from the service manual and an ammeter (and the knowledge to use it) to track this down.

Alternatively, see my next post for some hints. The fact you have noise that goes away when you disconnect it is pretty good indication that you are very close to the culprit.
For the battery to hold up five or six days, I'm surprised, since the likely culprits would often flow more current than that!

 

Essentially, that connector is for various wires from the chassis to the engine block. Wires directly from the ECU to the block (like the wires that run the plug coil packs, fuel injectors or various sensors) do not pass thru that connector. That connector is more for switched power feeds to various appliances on the block, like the air pump, A/C clutch or the coil packs themselves.

Here are the pinouts, I am sure of all but pin 2:

Pin 1* - Air pump relay control line - operated by ECM via Fuse 2 on Relay Module.
Pin 2 - SRT ONLY - either supercharger clutch (Probably) or Intercooler pump (probably not, since it's not on the engine block).
Pin 3 - A/C compressor clutch - fused via fuse 35 or 37 (manual does not tell us).
Pin 4* - Feeds coil packs and noise suppressors via Fuse 11.
Pin 5* - "Battery/Alternator" indicator - goes from alternator tertiary output to the instrument panel.
Pin 6 - Engine starter motor solenoid - fed from pulse module, not directly fused.

Those with * are those I'd suspect in your case as these are 'battery hot' feeds - other pins are switch off with the key off, you can verify this with a voltmeter. And you SHOULD verify this, as there are errors in the manual.

A leaky coil pack pass transistor would certainly cause this, pulling fuse 11 would tell you if that was the case.