ZedZilla

Hi all,

My 280Z has a 4 pin ignition switch harness, or so it seems by looking at it. The wiring diagrams etc also show the harness leading up to a 4 wire harness plug for the ignition switch. This is apparently unusual as most Z cars have the 5 pin switch and harness plug...

Its all discussed in the thread previously posted, please read. I have posted the link below. There are pics of my car's plug and switch etc...and link to a wiring diagram for the 78 280Z.

https://www.zdriver.com/forum/showthread.php?t=23040

I hope someone here can confirm one way or the other....cause without this fault fixed my car can not stay running. As soon as I let the key return to "run" after the car has started it turns off. At that point with the key in the ignition switch, there is no power to the dash or any other lights / accessories....

Any help would be appreciated...

snwbrderphat540

just curious, how was it running before and what did you do and why did you do it that this problem started occuring?

ZedZilla

hey snw, I actually have never had it running yet. Just bought it a couple of months ago.

The previous owner's son had inherited it from his father. By the looks of things, he tried to get it going and I don't know if he was the one that changed the switch to a 5 - pin but that what was in it when I got it. It looked absolutely new when I took it out. The problem of having a dead spot in the switch was there from day one when I tried to start it once I got it home. Its only now that I have had some time to work on it that I have seen the switch as a potential problem. I have changed that switch with two other ones, one that I knew was working from before. And nada luck.

Having said that, there may be other things contributing to the car not starting but, as it seems to me, this is definitely an issue I need to figure out as well.

I am just having such a hard time with the possibility that my Z can have a 4-wire harness plug but a 5-pin switch. It just doesn't make logical sense...the pin is there in the switch but there is nothing in the corresponding spot within the harness plug....its frustrating as heck!

Can anyone with a 78 Z please please check this in their car and let me know. That would at least eliminate one issue here.

snwbrderphat540

ill ask my dad he used to own a 78

ZedZilla

Thanks a lot dude.

I am surprised no one else with a 78 Z has noticed / experienced this before....

I haver searched quite a bit on sites such as Hybridz, atlanticz and ZCAR.com. But haven't found an actual answer so far...

jfairladyz

I still cant help but think that the ignition switch isnt the problem. have you done any voltage or continuity tests to make sure the circuits are ok? If you run a jumper wire between the power in and the ignition portions of the switches connector and your warning lights dont come on then the problem is definitely not with the switch. The reason its a 4 prong switch and not 5 is probably the absence of the RUN part of the switch.

snwbrderphat540

i also kinda think that ^^^ but im still gonna ask, tommorow.... if i remember. lol

ZedZilla

J, the switch that I have now is a 5 - pin switch. It does have a separate pin for the RUN part, however the matching spot in the plug harness is non-existent, being a 4 wire plug.

All other connections are functional, as in the buzzer is on when the keys are in the ignition with the switch being OFF, the idiot lights come on when the switch is at ACC, then at the ON/RUN position there are no dash lights on and nothing else works either (no head lights, turn signals, wipers, etc etc), then at the START position the car turns over and starts only to die as soon as I release the key for it to return to the ON/RUN spot.

The ON/RUN spot has no power when the switch is at that position because there is no wire from the harness at that spot, even though the pin in the switch is there. Call me crazy but, that appears to be a total mismatch. Why would the switch have an extra pin when the wire plug only has 4 wires that, in a normally starting car, are needed to make all necessary connections to make the car's ignition go from OFF, get the ACCESSORIES on, Turn ON and then START before returning to ON/RUN position.

This only leads me to believe that the switch that will run the car will be a 4 pin switch.

Having said that though, I have'nt manually checked the continuity of the wire harness plug. Do you think I should be doing that? and what can I expect to be different from what I already know.


Thanks snw. That would help.

snwbrderphat540

hmmm, so its dead in run but acc. works? you should just try switching teh pin position in teh harness plug then (temporarily) and see if acc will do nothin and then it starts and stays running.