Hey guys just made an account because it seems no one to own a Z31 has had this set of issues and I just want to make my dream car run. Not even my buddy who owns the exact same car (except transmission) or my other buddy who was a Nissan technician can figure this out.

The car:
-1985 Nissan Z31 NA GL trim automatic
-completely stock
-114k on odo
-Unnaturally clean interior

History:
Owned by a responsible lady for decades who bought it from dealership new. Her husband sold it to the guy I bought it from near San Antonio, Texas. Spent a few years under a tarp outside in his backyard. Looked like an animal called the engine bay home at one point but has since vacated. More specifically, it lived between the battery and the wheel arch. I looked meticulously for damage to the wiring harness but was unable to find even a scratch.

Issues:
I went to start the car but of course battery was dead. I bought a new one and left it connected but it was drained within 2 days. My buddies and I figured I just left the door slightly open so it was drawing power. Got it charged, put it back in the car and went to start it. The engine cranked and the starter sounded healthy but it wouldn't turn over. I checked the fuse box and the fuses were fine. I even swapped the fuel pump fuse and related fuses with others to no avail. I bought a Walbro GSS342 255 LPH fuel pump kit. Whie installing it I realized the fuel tank and the lines were completely clogged so I cleared everything. I installed the pump and put everything back together. I turned the key to the "ON" position but I couldn't hear the fuel pump running. I tried to start the car but with the same result as before. My Nissan tech friend used a multimeter to read the current to the fuel pump. I went to start the car with him reading the male connector that plugs into the female connector coming from the fuel pump but there was no current. He tried reading every possible orientation of the connector with the same result. He then tried reading the fuel pump relay behind the fake vent in the passenger side door jam. There was current. I tried using my other buddy's fuel pump relay with no success. I tried using a relay from the engine bay with no success. We all assumed there was an issue with the wiring from the relay to the connector so I exposed all of that wiring and found it to be completely mint. So please, Z gods, help me. Is it the ECU? Did we wire the fuel pump incorrectly? I doubt that but if you guys think its probable then I'll go through the painstaking work of dropping the gas tank again.

Other electrical issues
-No light to gauge cluster
-No light to head unit except backlight for digital clock
-No woman's voice telling me "light's are on" or "door is ajar"

-power seats work
-power side mirrors work
-power windows work

 

So I was poking around the wiring harness near the fusible link box and battery. I removed the battery and disconnected the box from the car frame which revealed the part of the harness which goes through the firewall. Below is what I saw hidden between the battery tray and the body, the 12v wire that supplies power to the dash lights is exposed through its, for lack of a better word, sheathe. The wire itself looks a bit corroded so I'm going to repair it and add some additional bolstering to that part of the harness. Will update later.

 

So I cut the 12v power wire and used a crimp connector to reconnect the two ends. That solved absolutely nothing. However, my friend who has the fabled godly mechanic touch went to the fusible link box next to the battery and twisted the black wire on the main power link, after a bit of coercion all of the lights in the car lit up like a Christmas tree. The woman started telling me "lights are on", the dash lights came on, pop up headlights worked, head unit, overdrive switch button next to the shifter, headlamp, hazards, wipers, like 95% of the things that weren't working before.

The only issue, and I mean literally the only issue this car has mechanically, is the fuel pump not getting power passed the relay in the door jam.

So, guys, if only your windows, high beams, electric seats, and power mirrors are working, check. The. Fusible. Links. Twist it, bop it, whatever. Even if that doesn't work, just buy replacements because those things can be absolutely shot without any indication.

 

I stripped all of the wires on the linkable fuses and only the main power one (further to the right, black with the red cap) had burnt out. I used some copper wire lying around and used pinch solders to connect the wires back together (ghetto asf I know) and now things are getting power consistently.

However, I noticed the blower motor only works when its less than 90F degrees outside (I live in Texas)
Also, according to the battery volt meter on the dash, the battery is being absolutely drained. Tonight I went to sit in the car, turned the key to on, turned on blower motor, headlamp, hazards, etc. just to see what would happen to the battery voltage. The voltage went from a cool ~11v to ~9v in the span of 20 seconds so that's pretty neat. This is nothing new of course because as I mentioned before, the battery was drained after being plugged in for ~3 days. I thought maybe it was the anti-theft system being retarded because the "security" light on my dash would flash whenever the battery was connected without stopping like other posts say it should. So I pulled the fuse in the driver's side floor panel. The light stopped but that clearly had little impact on the battery drain. Clearly there's something totally ****ed with the electrical circuit somewhere but I have no clue what. I searched all over the engine bay for connections that may be corroded but I just can't find anything wrong. Ive checked all of the relays as well including the hidden neon green one I just found beside the battery tucked into the fender well.

Forum posts with troubleshooting guides have gotten me no where so I'm either retarded or this is an issue so rare that I'll need to spend a lot of time learning about electronics and circuits to solve. Maybe both.

I know i'm shouting into the void without replies but maybe some one will throw some suggestions my way. I will try anything you guys tell me (except scrap the whole project of course)

 

Have you tried the thing where you connect a light in series with the battery? It lights up to show the drain then you pull fuses until the light dims to identify the drains.

 

Ive never heard of that method. Thank you for the suggestion. I'll definitely try that if battery drain is whats causing this new issue ive found.

I realized that while the fuel pump relay connector is getting power, the relay itself is not clicking. The connector is measuring 10.7v which should be enough to trigger the magnet inside of the relay but its just not. I swapped the relay with others I know are working and still nothing.

I can only think of two things which may be causing the relay not to click
1. While ~85% voltage (>10.3v) may be enough to trigger the magnet in a relay, Ive read that older vehicles really don't like getting less voltage than they should, even if it SHOULD be enough to trigger the relay in theory.
2. There's something wrong with the wires somewhere for some reason

But I'm going to use Occam's razor and assume number 1 is the cause. So i'm going to go to Autozone and pick up a newer relay to see if the relays made today are okay with getting less power to click. If a brand new relay doesn't work then I'll probably go with Cobalt's suggestion and fix the power drain/leak in power from the battery to the electrical systems. Maybe its not the relay that isn't okay with not getting ideal power, but something else in the circuit. I will update after trying to solve these issues.

 

I spent days trying to track down an electrical issue only to find that yep it was the most likely cause.

Good luck.

It is pretty dead around here.

 

Apparently the relays are an OEM part so I guess i'll just have to look for a short to ground in the engine bay. Its probably the ****ing animal that was living in the engine bay who caused it.

 

I just realized that when I turn the ignition to ON every relay in the relay box clicks. No other relays in the car click though. Not the green or black ones behind the battery in the wheel well or the relay in the door jam. The green relay connector is not getting power but the door jam relay connector is.
I assume every relay in the car is supposed to click then when the ignition is on but I can't find anything online to confirm this assumption. If I knew whether they are all supposed to click I would be able to search more specifically.