Currently looking to wire a Haltech IC7 dash to my ADM 2004 SE/MSM, replacing the cluster, fed from the Link but also needing inputs for lights, ABS, bag, blinkers, etc. Planning on tapping the existing cluster harness for those.

Option 1 - throw caution to the wind, cut the relevant wires, re-pin to a 6 or 8-pin connector, job done. Pro: not likely to want to go back so cut to the chase and do it the simple way. Con: going back messy, but unlikely.
Option 2 - splice in new wires leaving exiting wiring/plugs useable. Pro: best of both worlds, flexible into the unknown future. Con: Finniky, could have continuity problems.
Option 3 - de-pin relevant wires, cannabalise the spare harness for a suitable m/f connector pair for the relevant wires. Pro. Neat, reversable. Con: Doable? I don't know ...

So has anyone tried Option 3, on any connector on the stock harness? Are the pins uniform though the harness, I'm guessing not but is there any info out there?

Pending any thoughts and suggestions here, next week I will pull out that harness and do some playing around with it. I will also use the time to nail down exactly how many wires I am going to need, plus maybe a couple of spares.

 

Having not looked into it at all, I'd probably clip the wires 10" back from the cluster and throw Deutsch connectors (or whatever your favorite flavor is) on both sides. Then you can put a mating connector on the IC7 and a mating connector on the OEM dash and in theory hotswap between the two. I believe that's what you're describing in option 3.

I don't see why it wouldn't work, but I also haven't ever been back there or looked into it at all.

I helped a friend wire his active center diff and fuel level signals into his IC7 which is my only experience with it. For that I got some crimp connectors, split the wiring and crimped a new wire on to feed to the IC7. So the OEM plug is still there (disconnected, but still getting signals) and there's a plug piggybacked on that goes to the IC7. It's working fine, but I don't think I'd go that route if I was going to go back and do it again.

I used the little crimp/splice connectors like seen below.

 

I went with option #3 for my MS3 when I put a VVT into my NA. I would not do it again.

The wires you need are never in the easiest bundle, and are typically spread across multiple connectors. If you’ve got shop manual wiring diagrams, try tracing out the wires you need. They’ll tie into other circuits, have weird ground points, etc.

That’s if you were to unplug the connectors back deeper in the harness. From my experience with the connectors at the actual dash (NA, not NB, but I think they’re similar), you’re not going to find an off-the-shelf mating connector for those. You could make your own, but I wouldn’t put money on their reliability.

My approach would be slightly different than suggested above. I would cut the harnesses back about 6-10” back from the cluster connector, but go directly to the type of inline crimp described above, with Raychem SCL over each splice. (Description here, with Sumitomo alternative described as well, in case you’re not familiar. I don’t expect buying from them is sane for you https://www.prowireusa.com/raychem-s...ive-lined.html ) It gives you the chance to go back to stock fairly easily, using either the original cut-offs or the spares if you need the extra length. You can either stagger the cuts/splices to keep the harness slim, or just live with the big lump of cutting them all off at the same place.

Please, please, please triple count and map out how you will wire up the IC-7 pin usage. One issue I have with Haltech stuff is that their number and distribution of in, out, analog, digital, do not mesh with my needs. Also, plan your sensor grounds, especially for the fuel gauge.

Someone recently posted a UC10 custom dash that looks exactly like a NA dash to the Haltech custom dash Facebook group, FWIW.

 

Yes, I have seen a YT vid of the 'piggyback' spliced connection, using those connectors. The vid was quite informative on the practical level, but not MX5/Miata, not even Mazda. Nevertheless the approach and tips were solid, I suspect I will be watching that one again.

Agree, finding a matching connector is so unlikely I am not even thinking about it. I have done some cursory searching, but no dice and it doesn't seem worth wasting my time on going further. TBB, I am not looking at doing no more than pulling the cluster, it might be different if I was planning on pulling the dash for other reasons and could access wires further back in the loom. I have the wiring diagrams for the car, and you are right, they will be scattered across the three connectors.

I want to have a look at my spare harness before I make a call, but terminating the relevant wires at connectors with mating connectors wired back to the IC7 may be the cleanest and simplest. The trick will be making sure I have the right wires, for some functions there appear to be multiple wires, but that is common to whatever method is selected.

Yes, I saw that dash, I have joined that group to look for ideas/inspiration, and someone who I can commission - while I want to DIY all the things, these days I am trying to be a bit more selective how I use my time.

 

Apparently the connector is also used in Ford models according to some reddit thread.

 

Thanks Stoffi, done some searching but nothing as yet, will continue. Note that I have the harness plugs, it is the mating plugs (which of course are part of the enclosure (IIRC)) that would be useful. Still haven't got the old harness down yet, maybe tomorrow now that a job that was scheduled has disappeared ...