Identifying which connector goes where?

[erik325i]

Up until now, every time I've replaced a wiring harness, I labeled each connector before removing it. This time, since I'm converting an s52 to OBD1, the wiring harness is different and the OBD1 harness I'm using was not labeled before it was removed from the original car.

What is the best way to identify which connectors are meant for which components?
Thanks

Erik

[samiam3356]

I ran current through each one of mine and verified it against the manual. Everyone, checked out except the TPS. That was the last 3 wire connector left so it was easy to figure out.

[Gnarles]

Get the pinout chart for the DME and check for continuity between a pin and it's respective sensor. This is what I did for my harness when converting my S52 to OBD1.

[SamE30e]

Theres only like 7 plugs, it's not hard to mess up.

On the maf harness there is a plug thats the purge valve, so there 2 connectors gone.

Coming from the harness there a 3 pin connector thats longer then usual, that's TPS. Theres also a 2 pin that is as long as the TPS thats IAT

Theres 3 more 3 pins, 1 is ICV, 1 is Crank and 1 is Cam. The ICV has 3 thick wires in it, you can feel them.

The Cam and Crank are essentially the same so hook them up, if you're car doesn't start, switch them.

Then theres 3 2 pin connectors, 1 has 2 contacts in it, and is probably blue, thats the DME coolant sensor.

Then the other two are oil pressure and the cluster coolant sensor, ground one out and see if the oil pressure light turns off, if it does then thats where it goes.

[samiam3356]

Knock sensors are 3 pins to.

[SamE30e]

Didn't he convert to OBD I?

[7pilot]

You can compare the wire codes of the harness to the ETM for the engine/harness. This is the best bet as you can reference the codes in your notes for future trouble shooting.
You can lay the harness out on the floor, then pay attention to how the wires want to naturally sit.
The component sub looms are usually just long enough to reach their assigned targets.
The toughie will be the Knock sensors.
The reverse light switch subharness is siamesed to the O2 sensor subharness and these "go against the flow" and go behind the head from the LH side of the block.
You'll need an extension harness for the OBD1 harness to the OBD2 vanos cylinder.

m

[erik325i]

Cool, I got most of the connectors accounted for by checking continuity to the ECU connector and comparing it to the ETM diagrams.
Thanks guys.

Erik

[Adrian_Visser]

I looked up the wiring colors in the etm and pulled back the boots on the connectors to compare. Most of the wire colors were correct. Then to be totally sure I rung out the connectors from the x20 and/or DME connector x6000 with a DMM on continuity beep mode. Reading through the whole etm took a while but I learned a bunch about the electrical so if I have troubles when I go to start I should have some idea of where to go.

[sharksforthecup]

+1 for using the wiring colors in the wiring diagram of a bentley.