Let's play... NAME THAT WIRE!

[RoCa]

Good Evening All,

Just doing some pre road checklist for my 1975 280z when I came across these wires and I wanted to make sure if these are necessary in order to drive because the car seems to run just fine.

First, we have here is a lose ground wire which I'm not sure where it connects.

Then, we have this wire which is just wrapped up in another wire. (see red circle)

which happens to be coming from the firewall...

Up next, the interior wires.

If anyone can identify these wires, It would be greatly appreciated! Thanks so much!

[SteveJ]

A previous owner really went to town on the wiring.

One issue with trying to identify the random wiring you show is that in many cases you made no effort to say where the other end of the wire went to. For instance, in the top picture, does the other end attach to the negative cable for the battery? If so, the previous owner probably used it for a chassis ground.

In picture 2, that's likely a ground wire. Buy a nice multimeter and learn how to use it. Then you can see if the wire is connected to the chassis ground.

I think another thread on this board suggested a wire like in picture 3 is involved with AC control.

Picture 4 shows door switch wires. You can probably just ignore those, at least for now.

Picture 5 - I'm not sure which 6-wire connector that is. Download a copy of the 75 FSM and look in the BE section. Match the wire colors to the descriptions to find the function.

Picture 6 -You know you're going to have to trace that one out. Maybe someone replaced the stock clock with a 1.5 volt clock. I hope you don't think it is stock.

In picture 7, are you referring to the wire with the inline fuse holder or the lug that is missing a wire?

[mjr45]

I am by no means an expert on wiring, but I agree with Steve, however, the 2 white wires in pic #4 are similar to my 75 and they don't connect anywhere, I think (wild guess) they were for some type of altitude adjustment for the ECM. The wire in pic #2 maybe for the water temp switch mine was similar. Pic #4 is some type of jacked up work around on a console connector, #6 probably the clock which has been redone, #7 a fused wire to the console probably a radio wire. All of these are just WAG's on my part, get a FSM and you can tell exactly what you are looking at.

[Wade Nelson]

I have to congratulate you on at least ATTEMPTING to identify and properly connect these wires instead of simply ignoring them, as so many others do.

Let's start with:

#1. It's not clear from the photo if that wire is insulated, or bare copper. If it's bare copper, then it MUST be a groundwire. It really doesn't matter WHERE you connect it, either to the body, the frame, or the engine block. The only important thing is that you remove the paint/rust/corrosion from beneath where you mount it, and lightly sand the ring connector too before bolting it down to ensure a good connection. Where does the other end of the wire go? Was this some massive ground the PO (previous owner) installed for a stereo amplifier or something?

#2. Your only hope with that one is to trace it back through the firewall and see where it's coming from,.

Alternately, you could put a meter on it, first engine off, then engine running. Start by seeing if it has any voltage on it in either of those conditions. If not, check and see if it has continuity to ground. If it has no voltage, and no continuity, I'd wrap the end in tape and forget about it. If it DOES receive power A) continuously, ignition on, C) engine running, D) cranking, then I'd still wrap it in tape and keep it in mind when you later discover something that NEEDS that power. Ditto if it shows continuity to ground with ABC or D. One day you'll discover something not working, like windshield wipers, and realize where that wire is supopsed to go.

Interior wires --- not a clue. Are they OEM or added by the PO? The connectors look factory. Are they BOTH white, with no stripe? I'm thinking perhaps speaker wires for a speaker not in the door on this particular model. Again, test 'em with the meter and see if either or both shows power or continuity to ground.

Battery holder? As the previous commenter suggested, following that wire to it's destination is your only real choice there. OR, you could remove the battery, apply 12V instead, and watch for smoke at the other end.....

I don't see a loose wire in the last picture. I see both the blue lug, and the inline fuse holder, both of which appear (to me) to have wires attached. Is that a stray blue wire at the top of the photo? Factory wire or something PO added?

HTH, and good luck.

[RoCa]

Sorry for the delay on my reply, I haven't had the chance to get back on in a while. The wire in the first pic is actually copper and you can see where it is coming from on the 3rd pic which is from the firewall. Also, I forgot to mention that I do not have AC and heater on this car. I am also missing a switch from the center console to the right side of the hazard light switch. The last pic confuses me because it is a inline fuse holder but the end doesnt seem to connect to anywhere nor hold anything. Here is a better pic.

I don't know what the blue thing is about either...

BTW I do have a copy of the FSM and Haynes repair manual but I'm just really confused so I really appreciate your help. Thanks again!

[Powderkeg]

RoCa,

The wire coming from the engine bay firewall in picture #3 goes to the white plastic vacuum canister in the engine bay.

Sorry I couldn't be of more help.

Dave Ruiz