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View Full Version : RB25DET lower harness has extra plugs and wires?

KPNITRL
07-01-2008, 10:01 PM
Hi, thanks for clicking.
So I'm in the final stages of wiring my RB25 into my S13 and I am totally at a loss with some extra plugs. I tried posting this on another forum but surprisingly didn't have much help. I hope some of you RB pros has some insight.

Im using a KA harness and the plugs off of the RB25
On to the pics.
http://i26.photobucket.com/albums/c137/R33_Drift/DSC04886.jpg
So at the back of the harness there is the RB VSS plug that I need to transfer to the KA harness right? Well I dont know where or what to do with the other two plugs that are at the end of the RB harness (pic below)
http://i26.photobucket.com/albums/c137/R33_Drift/DSC04888.jpg
Because at the end of the KA harness this is it
http://i26.photobucket.com/albums/c137/R33_Drift/DSC04889.jpg

Then on the alternator side of the RB harness there is an extra brown plug that plugs into the AC I believe, but none on the KA. I plan on running AC so I figure I would need this plugged in, no?
http://i26.photobucket.com/albums/c137/R33_Drift/DSC04890.jpg
What the crap are these for? Again off of the RB harness. According to what I found, the square plug has some wires that are coming from the back of the harness. One color that stood out was a green with an orange stripe which I thought was the neutral something or other, I figure this is important as well.
http://i26.photobucket.com/albums/c137/R33_Drift/DSC04892.jpg
Again, thank you for any help. I tried looking online for a while and the best I could find was from RaceBread (awesome site) But didnt really answer some of my questions.
sillyvia13
07-01-2008, 10:07 PM
you should find a fsm and ecu pin out...
will help you best...
you can test wires find out where in ecu they are then you can find # in pinout and bam.

I dropped mine in and used like 4 wires...lol...its just a race toilet. but its runs.
KPNITRL
07-01-2008, 10:17 PM
Thanks for the response. I actually have the R33 fsm and a 240sx fsm but no real luck with the lower harness. All I can find is a diagram of where the lower harness goes on the car. But no info on which is what.

lol, "a race toilet" thanks for the laugh.
Z U L8R
07-02-2008, 08:05 AM
use your car's lower harness not the rb lower harness. cut out the knock sensors and idle control plugs from the rb's lower harness. for the reverse lights and all that, cut the plugs off the very end of the rb lower harness and splice them to your lower harness in the coordinating positions.

Dave
KPNITRL
07-02-2008, 11:53 AM
use your car's lower harness not the rb lower harness. cut out the knock sensors and idle control plugs from the rb's lower harness. for the reverse lights and all that, cut the plugs off the very end of the rb lower harness and splice them to your lower harness in the coordinating positions.

Dave

Thanks for the reply. I am using the cars lower harness but at the end that harness there is only the VSS plug to tap into. But on the RB harness there is the VSS plug, and two other plugs which lead to a square plug at the other side of the RB harness. which I'm guessing would be the reverse lights and such
Z U L8R
07-02-2008, 07:51 PM
sounds like you got it under control then....what's not making sense to you?

Dave
KPNITRL
07-03-2008, 07:56 AM
its those two plugs on the RB harness (2nd pic). I'm wondering if I need to somehow wire it to the KA harness. But I don't even know what they are for.
Z U L8R
07-03-2008, 03:54 PM
as far as the lower harness and the tranny sensors are concerned. you have a park neutral switch (green/orange) , the speed sensor (yellow/green), the reverse switch to kick on your reverse lights, and your 5th gear position switch.

depending on how your engine's wired in essentially the only things you need to worry about is the p/n switch, reverse lights , and speedo. even if you didn't have any of em wired up the motor will still run though.

if you want. make two columns. give each plug on your rb harness a letter, then write down what 2 wire colors they have. do the same for the ka lower harness plugs, and i'll tell you what to do.

Dave
KPNITRL
07-07-2008, 07:45 PM
Thanks so much for the continued help.

ok this is what I got. Hopefully it helps.

On the RB side:
Here are the three end plugs:
http://i26.photobucket.com/albums/c137/R33_Drift/RB_plugs.jpg

A) yellow/purple
grey/red

B) red
green/blue

C) black
green/orange

On the end of the KA harness all there is, is the VSS plug:
http://i26.photobucket.com/albums/c137/R33_Drift/KA_VSSplug.jpg

1) yellow/blue
yellow/black

Which Im pretty sure that my KA "1" plugs in with my RB "A" for the VSS

Now on the other end of the 240sx lower harness I have this plug:
http://i26.photobucket.com/albums/c137/R33_Drift/KA_plugfusebox.jpg

2)
__l---l__
l 1.....2 l
l 3.....4 l
--------
1) yellow/blue
2) white/red
3) yellow/black
4) yellow/white

Which I had to take from a car at the junkyard since I did not have a lower harness with my car.

So the plug that is on the chassis' fuse box is actually a bit different:
http://i26.photobucket.com/albums/c137/R33_Drift/Chassisplug.jpg

Chassis plug)

__l---l__
l 1 X 2 3 l
l 4 5 6 7 l
---------
1) green/blue
X) none
2) white/red
3) yellow/blue
4) green/white
5) green/orange
6) yellow/white
7) yellow/black

Which has more wires and makes more sense to me about the extra plugs that go on the RB tranny. So Im thinking that this is the extra plug that I would have to tap into to run the reverse, neutral, and 5th gear. Which by the way, why is there a sensor for the 5th gear?

Again, thanks for the help, hopefully my "charts" give you a better idea of what I am working with.