How do I replace the engine wiring harness in an NB
 

I'm attempting to help a friend rebuild his 2001 LE, after a small bit of fire in the engine bay. I have the kink to the FSM, however, it does not discuss the actual removal of the engine wiring harness whatsoever. I have another full wiring harness on the way.

I have pulled the dashboard, minus the huge 3*3 wiring connector holding it at bay.
It looks like I need to pull a bit of the AC system to re-run the wires through the firewall.

I will also need to replace the other wiring, which powers the starter/alternator. All the connectors were melted down.

Has anyone pulled the wiring out of their NB; and could you offer any advice/tips to make the job easier? Thanks for your time!

When I did my my v8 swap in my '01, my motor was already out so I removed the dash, disconnected the main plug (X16 blue plug which I think that is to the right and under the gauge pod area), and just pulled everything through the engine bay and removed the whole thing. Since I removed AC with my swap, I also had the heater core and plastic box out which I think the harness runs behind.

damn, I'm hoping that pulling the heater core/a/c condenser is not really needed. Trying to get this car roadworthy asap.

Yeah dude, a fire in general means you should be prepared to disassemble the car.

Sounds like dash is just minimally held in at this point. A/C and heater core are only another few minutes of your time. It is, what it is...

Yeah, you are right. I'm just used to the relative simplicity of my NA. Far less everything involved.

I know the drill well... always something when you just want to finish the task at hand.

Especially when it's free labor, and not my car, lol

Check out the last few pages of this build thread:

https://www.miataturbo.net/build-threads-57/2jz-miata-build-thread-41570/

Sean made a bulkhead connector for his harness. If you work on your car a lot, this feature would be very nice to have.

Can you PM me a link to the FSM?

look for the FSM link in the Saved Posts thread.

FWIW: There are 3 wiring harness on the 2001 model.

The largest one runs from the driver headlight, into and behind the dash, and out to the psgr headlight.
--Luckily, I do not have to pull this one, as it would require removing the a/c condenser, and the heater core.

The second harness actually plugs into the ECU, and into the first wining bundle. After disconnecting, This bundle can be pulled out from under the engine bay. Putting a new one in may prove difficult without removing the heater core. This is the one that sustained the most damage.

The 3rd runs from the starter/alternator, down the PPF, to the battery. I need to replace this one as well. Have not looked into removing it yet.

As others have said, it's really not a big deal to remove the heater core. Taking out the dash is the big deal. The heater core is pretty simple once that's done.

Glad to see you hanging out here!

Yeah, looks like the biggest pain of the heater core is getting the hoses off without damaging the aluminum/copper lines. I was more worried that I would have to remove the a/c condenser, which does not look to be the case.

Now I have to wait for the owner to get in some new parts from FFS, a non-charred ECU harness, and the starter/alternator harness.

RE: 2004 MazdaSpeed Miata

I realize that this is an old tread, but by any chance someone knows if I can replace the engine harness (rodent damage) without removing the dash? I just inherited this car and so far the only damage I had been able to see is to the connectors of the coil packs and the passenger side headlight.

I just bought a used complete engine harness and saw the big round firewall seal, making me believe that it would Not be as easy as I originally thought. Thank you in advance for your comments!

Pull the dash. IIRC there are clips securing the harness behind the HVAC, they might even be behind the sound deadening too. Assuming the damage is all on the engine side of the firewall, you could cut it and rejoin with connectors or otherwise, not my cup of tea though.

The alternative is to just replace whatever is obviously damaged. I would not attempt that until I had some confidence that I had identified all the damage, if it doesn't fix it you may have to start all over again with another engine harness and pulling the dash anyway..

I did this recently to replace a leaking heater core (that's another thing you can do while in there), it's a big job but not difficult, I did it solo. Just make sure you know where everything goes, I took lots of photos of connectors, control connections, etc as I disassembled it which proved useful on putting it together again. My build thread also has some tips, learnings etc.