X20 plug wire ID help

[kroberts]

Take a look at these two wires for me PLEASE.



My harness is for a '95 325. These wires come out of the same lead that the diagnostic pulg is on. They come out of the right (passenger) side of the plastic harness box, both appear to be ground wires but I obviously want to verify this. I got out my multimeter and checked their continuity. The larger one is hot to x20 pin 17, the smaller one to pin 16.

I bought this harness new so I wasn't able to record what the wires were connected to before removal.

TIA,

kr

[BigD]

The wire that is bundled with the diagnostic connector is its ground (your car may have a stud already on the strut tower), the other is the harness power connector, it goes on the battery junction. DO NOT FUCK THIS ONE UP!

[kroberts]

D, why do they both ring to the x20 connector? I'm puzzled.

[BigD]

D, why do they both ring to the x20 connector? I'm puzzled.

Not sure, maybe the X20 is powered and grounded via both of those? The description of the power lead I have is that it's the main power supply of the whole harness...

[Mike B.]

BigD is right, just wire it up like he says.

You can also pull back the cover to verify which is power and which is ground.

Pins 16 and 17 on the X20 are diagnostic pins (TDX/RDX Datalink), which is probably why you have continuity.

[kroberts]

Excellent! Thanks fellas.

[btec116]

By memory, doesn't that power go to the starter solenoid? I'm not sure, I might be thinking of the wrong wire. Check its colour and you'll know.
Also, I took my ground through the firewall with the ECU plug, and grounded it under the dash. Super-tidy, if you dont have a proper ground location within reach in the engine bay.