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D16A EK9 Sedan
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Discussion Starter · #1 ·
Hey guys

We pulled the harness from my D15Z4 (right hand drive EK Civic, OBD2) and need some help identifying the plugs on the harness.

The plan is to create a harness in the future and I'd like to have these notes at hand and also if they may help others in the community. (Sorry for the crude layout and presentation below. I will update a cleaned up version should all/most of the plugs be identified)

I've attached a photo of what the harness looks like:

A picture of a D15Z4 harness laid out with each plug numbered. Unknown plugs are labelled as ? while known plugs are given their correct name or assumed name.

☝ — Each terminal is labelled from 1 to 26 from right to left. At each branch going from right to left, branches at the top is numbered before branches at the bottom. Terminal 27 is basically a dummy, but would still like to know what its potential use is.

Thanks 🙂
 

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93 Civic HB SI
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Starting from right to left (other folks chime in, feel free to call BS on anything I might say incorrect)


3 - Is a connector that connects to something near or on the HVAC box, cant remember exactly what this is. I despise HVAC on all my cars, so I've lost frame of reference lol.

27 - Splice pack?

8 - MAP sensor

9 - Intake Air Temperature sensor with sensor still connected (the sensor body pushes through a grommet found in the air filter box on the Z4)

10 - Injector #1

11 - Injector #2

12 - Injector #3

13 - Injector #4

14 - Idle Air Control Valve

15 - TPS Sensor

16 and 17 - Junction connectors for power/ground/other common things, leave these alone, they just "hang out". The "end cap plugs" installed into these connectors are bridges that join/connect other wires in the harness. If you take one apart and pop a plug out, you'll see what I mean.

18 - EVAP Purge solenoid

19 - Thermostat ground? Is this an eyelet with a bunch of black wires leading to it. If so, this is a primary source of ground for many important components, and usually attaches to a bolt near or on the thermostat housing.

21 - Starter solenoid female spade connector

22 - O2 sensor (not sure if upstream or downstream, but harness length when installed to engine will determine which sensor it goes to)

23 - Instrument Cluster Coolant Temp sensor

24 - Engine ECU Coolant Temp sensor

26 - O2 sensor (not sure if upstream or downstream, but harness length when installed to engine will determine which sensor it goes to)
 

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Reverse switch has to be in there somewhere, and so does VSS, unless you have a cable speedo.

#3 connects to the body harness. It’s how the gauge gets signal from OPS and H20, among other things. It should be C131 connector if you’ve got the FSM (it is for CDM/USDM spec, maybe different for you).

#27 is power/ground distribution.

Are you going to be running new wire and pins/seals or just soldering the OEM wires? I’m in the middle of gathering supplies for a new harness myself, so I can provide part numbers once I get them all figured out. I’ve been (slowly) going through my FSM as a cross reference too and hope to have everything mapped out over the winter.
 

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D16A EK9 Sedan
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Discussion Starter · #4 ·
Thanks so much @drtalon123 and @bumpstick 💯

19 - Thermostat ground? Is this an eyelet with a bunch of black wires leading to it. If so, this is a primary source of ground for many important components, and usually attaches to a bolt near or on the thermostat housing.
Yes, there are four wires that run to it

#27 is power/ground distribution.
That wires on it just run to sealed-off plastic end with no pins or anything -- it's just plastic

Are you going to be running new wire and pins/seals or just soldering the OEM wires? I’m in the middle of gathering supplies for a new harness myself, so I can provide part numbers once I get them all figured out. I’ve been (slowly) going through my FSM as a cross reference too and hope to have everything mapped out over the winter.
The plan is run new wires, reuse the hard-to-find OEM connectors, and, if budget allows, replace the remaining connectors with racespeconline ones. I should be replacing wires as well with GXL. I would really appreciate getting the part numbers. It's going to make things easier. And it will help anyone building a harness. The plan is to make a club-spec tucked harness with Raychem SCL sheathing. Been thinking of placing a bulkhead connector on the firewall so that should the ECU be replaced, we can simply run a new wiring only on the ECU side. That's the plan

Are you going to be reusing OEM color code?
 

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I didn’t plan on using the OEM colors, instead I was going to keep it a little more simple. My thought was to mainly use black or white and do something like green for signal grounds and yellow for power. It’s cheaper to buy spools of 100’ or 500’ of all one color than to get smaller spools of 25’ and 50’ of different colors, especially when dealing with ETFE wire.
Honestly you can save some money by reusing the OEM connectors and just buying new terminals and seals. The connectors don’t really wear out
 

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OBD1 ECU connectors:
TYCO/AMP Multilock Hybrid
16-pin 174514-x (x denotes color)
22-pin 174515-x (x denotes color)
26-pin 174516-x (x denotes color)
For colors, yellow = 7, gray = 6, blue = 5, and white = 1.
Female terminals for these connectors:
Large 173716-1
Small 173630-1
The number after the dash denotes material/finish. 1 is tinned and is what the OEM terminals are.

VTEC solenoid:
Sumitomo HW Sealed 1-pin

IACV:
Sumitomo HX 090 Sealed 2-pin

IAT/ECT:
Sumitomo HW Sealed 2-pin

MAP/TPS:
Sumitomo HM Sealed 3-pin

Reverse:
Sumitomo TS 090 Sealed 2-pin

I’m missing some I’m sure but I’m still building my list.
I’m using OBD2 alt/distributor so the plugs aren’t the same as OBD1 and I’m not using a standard 4 wire O2 so I haven’t bothered looking those up but they are Sumitomo as well.
The terminals/seals for these connectors are pretty easy to find once you know the series you are working with. Just figure out if you need male/female and then pick your gauge size. The seals are usually listed by inside diameter of the hole, so it’s best to know the outside diameter of your wire and pick the seal that covers that range. Most of the seals/terminals cover multiple series of connectors. I’d order 10-20% more than what you need because you will waste some figuring out your crimper/stripper settings.
Mouser has the best price on TYCO/AMP connectors but they don’t stock Sumitomo so you’ll have to find them somewhere else.
 
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