S13 Chassis harness

[JaredP]

Hey guys,

I just ran a quick search but couldnt find what i was looking for. how do you remove the chassis harness from an s13? im talking about the harness that goes beside the drivers seat, all the way back and around the trunk to behind the passenger. i have it unclipped/removed right up to the fusebox but i cant figure it out from there. i unbolted the fuse box from the frame, as well as the box above it (i'll get pics in the light) and i cant seem to pull them away enough to see if the harness plugs in but any help is appreciated

[ZootedS13]

if your talking about the entire chassy harness then your going to have to take off the dash and undo all the clips/zipties that are under there.

[JaredP]

yup thats what i was talking about. dash is already off and im in the midst of removing everything (right down to the headlight harnesses and just...well everything).

[Justinians_2:40]

Once you get behind the dash, you've got to track down each plug an unclip it, trust me, it's a b****. It's been like 4 years since I did mine, but I think you also have to unbolt the "Super Multi-Junction Box" or whatever they call it. Do you have an FSM?

[JaredP]

ya i downloaded an fsm...where in the fsm would it be? and whats this "super multi junction box" is it the thing in this pic here?

[Justinians_2:40]

Yea, I'm pretty sure it's that, it's kinda hard to tell from the pic, but I think so. If you have the same FSM I do, go to the Electrical Section (EL) > Harness Layout > scroll down a page or two, it will have a picture of all the connections under the dash. I was gonna try to upload a screenshot of it, but my photobucket account is being stupid.

*Edit: I just enlarged the picture, and yes, that is the SMJ. You have to pull that plastic cover off to get to the bolt that holds it in. There's some info on that a few pages below the harness layout page.

[JaredP]

dude you are the best. i'll look into it for sure

[JaredP]

just a question as to what a few things do...what do the:
-door lock timer
-headlight timer
- time control unit (is that just the clock?)

what do all those do, i just want to make sure before i remove them from the harness. also i just checked man and i cant seem to find harness layout anywhere in the fsm i have. i got the fsm off here if that helps

as for the smj, does it need to come "apart" or will it stay together so i can remove it and all the wires that are connected to it

[Justinians_2:40]

The SMJ will come apart, it's just like the plug that goes to the ecu, just a square version. Take that plastic covering piece off that covers the wires, then you can get to the bolt that is right in the center. The bolt won't come all the way out of the plug, it's meant to be like that, but loosen it until there is no more resistance, then it should come loose. Then just keep wiggling and pulling on the SMJ until it comes off, it's just one huge plug. If it seems stuck, try loosening the bolt some more.

As far as the door lock timer, headlight timer, and time control unit, I can't remember what they all do. I'm pretty sure the time control unit is an important one though, I'll take a look at my FSM and see if it's in there.

I can't remember where I got my FSM, but go to http://www.NissanTechDirectory.com; click "General Info/FSM's" then "240sx" and download the one that says "1989.pdf", I have it posted there.

[Justinians_2:40]

Just did some really quick research, the time control unit controls all your warning chimes (lights on, key in, stuff like that), illumination (your gauges, a/c, etc) and your intermittent setting on the windshield wipers.

[JaredP]

thakns man, so keep the time control unit..but im pretty sure i can get rid of all the wires for the door chime/door lock timer/ and headlight timer..but i'll see what i can find in that fsm

[JaredP]

does anyone know how to de-pin the SMJ?

[Justinians_2:40]

De-pin? What exactly are you trying to do?

[JaredP]

there were wires that went into the smj for stuff i was getting rid of...i was trying to depin them so i didnt have ends of wiring sticking out of the back of it

[JaredP]

there were wires that went into the smj for stuff i was getting rid of...i was trying to depin them so i didnt have ends of wiring sticking out of the back of it