Fried Electrical Harness?

gryffin13

Hey, so I was attempting to wire in a radar detector and a dash camera into the power lines running to my mirror. I thought I had everything perfect but as I was making the final installation I think I must have shorted something. I connected it and they both turned on, but then lost power and now I don't have power to the mirror, my heater/AC, my heated seats, and my sport-mode button. (I have a sport package+touring coupe).

At first I assumed (and hoped) that I just blew a fuse, but I checked and all are in tact.

So a couple questions that I'm hoping maybe someone here has the experience to answer as I've tried to google it and can't find what I'm looking for. 1) Based on the components that I've lost power to, is there a specific harness/component that I've likely ruined? 2) Any recommendations on how to go about fixing? Is this the kind of thing that is a big enough deal I really need to bring to a dealership?

Any info is appreciated - thanks!

SouthArk370Z

There is more than one fuse block in the 370Z. One in the cabin and one next to the battery (AKA: EPDM). Locations are in FSM (link in my sig) and Owner's Manual (same link).

Edit: there are also a few fusible links (see FSM).

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gryffin13

So I've checked 3 fuse locations: 2 in battery compartment and 1 in cabin. None have any blown fuses as far as I can tell. Fusible links are something I know nothing about. Looking at FSM didn't really clarify what I'm looking for. I googled them and it's a little hard to tell what I might be looking for. But I'll spend some time looking into the fusible links a bit more. Thanks for the input on a possible avenue to explore. Fingers crossed...

Edit: I was looking at owners manual, not FSM. I'll try to find the applicable FSM and read that. THanks.

SouthArk370Z

Looking at fuses is not at all reliable - you need to put an ohmmeter on them to be sure. OM and FSM will tell where the fuses for the items that are dead are located, so you can narrow your search.

I doubt if you have burnt up any wiring. Fuses are there to prevent that.

Fuses have uninsulated areas on each side of the fuse for your ohmmeter leads to make contact with the fuse element.

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gryffin13

Just to be sure I understand what you're saying - are you saying it's possible for a fuse to look unbroken, but if I actually measure the resistance, the electrical path will be broken?

I hadn't really considered that, but that's very good to know. I'll go measure some fuses. Because I really am hoping it's going to be something that easy to fix...

Jayhovah

that's what he's saying... i've seen it reported before right here on this forum =) I'd bet money it's just a fuse.

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2011 Nismo#91

After a month of problems with starting my car, replaced battery because it looked like it was giving low voltage at the point easy to measure when connected (beyond the fuse that looked good). Only to still have problems with the new battery; finally was checking if the socket of the fuse was bad, when removing the fuse it came apart in 2 parts because the internal connection had mechanically failed.


Good fuse right?


Nope it's bad.

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gryffin13

I will say that I have made the assumption that I could visually tell if a fuse is bad or not, so this has been a good learning experience no matter what.

That being said, I am still at a loss here. I've been pouring over the FSM and it doesn't really make sense to me. I see some of the electrical schematics, but I don't know what information to get out of them. I don't know how to read them to ascertain what else I should do. For example, I look at PG-39 and I can see that terminal number 5 is one that I have lost power too. And page PG-40, terminal no. 3. But I haven't lost that whole fuse block and I don't know where to actually physically find that terminal to check.
Pics of where I'm looking in the FSM: [1](https://i.imgur.com/M3bj3Hg.png) [2](https://i.imgur.com/Ckg4BaA.png)

To this point, I've basically just been looking at the labels on the fuses in the car. I've pulled anything that seems plausibly related (heater, mirror, heated seats, audio/mirror, elec parts, etc) and tested all of them and they all show good. If someone can help me understand what I should be looking for in the FSM I would really appreciate it.

Or is there something else I'm doing that is not thorough enough or doesn't make sense. I don't have much experience with things like this, but I'm trying to learn. I apologize if these are all obvious questions/answers.

SouthArk370Z

I'd suggest starting at the battery and following the wiring to one of the devices that is dead, checking for voltage at each point in the wiring that you can get to. When you find a spot without power, your problem is between there and the point you checked previously.

Or you can start at the dead device and follow the wiring back to the battery. when you get to a point with power, your problem is between there and previous point.

There is also the possibility that a power relay has gone bad or you lost power to the relay coil.

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OldGrayDog

Question you say you lost power after the install when you turned on the detector and camera. Have you disconected those items setting every thing back to stock to see if that solves issue?

For checking fuses, I simply put in fresh new fuses as a test.. they are cheap and available . As others have said I gave seen fuses blow in ways you will find hard to spot.

gryffin13

Yeah everything is disconnected and back to how it was. Something clearly is damaged though. And even though I haven't replaced all the fuses, I did take out a bunch to test them all and certainly didn't put them back in the same places and still the same components aren't working. So I don't think it's as simple as a fuse. I think it's something bigger.

SouthArk370Z

1: There's no need to remove the fuses to check them with a meter. If the circuit is unpowered, use Ohms (zero Ohms is good); if powered, use Volts (zero Volts is good).*
2: Where each fuse size goes is on the fuse panel lids (or the OM; or the FSM).

You may be right, but I doubt it. The wiring you were modifying is small enough that that wire would burn up before some of the larger wires that are involved.

*Edit: The readings may not be exactly zero but they should be very close.

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gryffin13

Oh haha. I didn't realize I could leave them in to test. Now I understand what you meant by there being an open spot to test...
Well given that, it certainly would be quicker to test, so I'll test literally every fuse now. But I did test most of them yesterday (any that sounded like they could remotely be relevant) and they seemed to be in working order.

Array

Confirm they are in the correct spots as after taking them out as well

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gryffin13

Well you were right and I'm so glad that my pessimism wasn't correct! Testing them without removing them went so much quicker so I could check them all easily. In case anyone else had a similar problem, the bad fuse was one labeled "meter".

I learned many things and had a good outcome. Thanks so much for your patience. Much appreciated!