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Not to thread jack, but if you have a chance can you take a snapshot of what the transmission harness looks like up close. Trying to track one down for my build and haven't had any luck. About this close to saying screw the auto GTT and swap in a 5 speed but then I'd have to deal with all the additional parts I need. GLW the build though.

I don’t have any photos mate. From what I’ve seen though, converting a manual harness into auto looks fairly complex. What happened to your harness? I can get photos but the cars currently in the workshop sorting the speedo. 

Had it sorted by a workshop, it ended up being a non turbo cluster which reads speed from the diff! So wasted a lot of time and money on something that was fairly straight forward.

Oh well, I bought another auto 34 today to convert, so should be able to do that fairly easily.

  • 2 weeks later...

I’m sorry to interject, but turbo and non-turbo have speedo location in different place?

so the wiring into the diff of non-turbo is the speedo? 

Your response was confusing.

I haven’t had a speedo in over a year after I converted a non turbo auto to manual turbo(did it all myself), the shops are asking for 140/hr to play guessing games with my car. Said it could take up to 10 hours. That’s 1400 for 2 wires...

Yes mate. So from what I’ve been told, non turbo and turbo clusters are different. Get yourself a non turbo cluster and see if you get the speedo back! Save yourself the labour!! I have the non turbo cluster in Adelaide if you want to try it. 

  • 5 months later...

Umm I’d have to dig up some old photos. Pretty easy to do a conversion though, I’ve done two now on jackstands in a shed. Message me if you need any other help if you’d like. I don’t often check this forum. 

  • 5 months later...
  • 1 year later...
  • 3 weeks later...

Okay ladies and gentleman.

I chose to reply this thread as this is the one that mostly comes up in google when you try to search for the topic in question.

I will mainly focus on the neutral sw in this case. Well, it also concerns the reverse SW.

When I did the MT conversion, I had huge trouble but very little time to sort everything out electrically. As such, I focused mainly on the visible stuff that matters in terms of MOT/shaken, which was the reverse lights and speedo. Here is where my memory is slightly hazy, but I believe what is needed is +12V to the reverse signal wire that is - again I believe - red. The neutral sensor was left disconnected, but I have since learned its significance in many things, such as calibration of the TPS, Hicas etc. This drove me on a quest to get it working as intended.

I found this thread a while ago but there were no answers so I just wired the switch to ground the appropriate pin (#39 if my memory serves) on the ECU directly, without utilizing the auto gearbox harness. 

However, during the past few days I opened the service manual and pulled out my multi meter and dug in to this while the car was on a lift and I had some time to spare and test things out.

The way I thought about both the reverse and neutral SW was that they are switches that ground the necessary wires when the appropriate gear is selected and the switch activated. But this is not the case. 

Well to be precise, it actually is the case, if the car is MT from the factory, but if you have the AT meter cluster with the AT christmas tree (P R N D 1 2) between the RPM and speedo, then things are different. Somewhere, likely in the meter cluster itself there are relays that - when activated - handle the switching of reverse lights and the neutral switch. In the case of neutral switch, the relay grounds the appropriate pin and it is likely the same happens with the reverse lamps as well. But it all goes through the christmas tree in the dash. 

And that christmas tree needs +12v to function so, instead of grounding the wires in the auto box loom, you actually need to switch +12v to the wires.

https://www.sau.com.au/forums/topic/139916-diy-r34-manual-conversion-using-r33-parts/

In this topic E_Lu-SHuN writes:

“The reverse switch consists of two brown wires(as seen in diagram) . One brown wire from the reverse switch joins together with the inhibitor(BLACK with Pink) and the power(GREY).

The REVERSE wire (red wire from the auto plug) connects onto the remaining brown wire of the reverse switch.

So for the reverse switch, one brown wire connects to the reverse signal(red wire) and the other brown wire joins with the inhibitor and power(3 joint wires). “

So what is happening here is that the inhibitor SW needs +12v, the reverse SW needs +12v and what is left out is that the same +12v is needed also for the neutral SW. 

The +12v is - apparently and in my best understanding and memory - provided with the GREY/RED wire. The RED is the reverse SW wire and the GREEN/WHITE wire is the neutral SW.

For TL;DR:

Split the GRAY with RED stripe wire (+12v) to three places:

  • Directly to BLACK with PURPLE stripe (Inhibitor SW so the car actually starts)

  • To Reverse SW and from that to RED wire in the AT loom.

  • To Neutral SW and from that to GREEN with WHITE stripe wire in the AT loom

This should end you up with all SWs working as intended and you should be able to observe this in the meter cluster (the R and N will light up in the christmas tree when reverse or neutral is selected).

Note that especially the neutral SW itself tends to be broken and or connecting only intermittently and you would be better off replacing it with a new one (as was the case and additional headache in my case). No need to drain oil from the box to do this (so long as your car is the right way up).

Apologies for the wall of text.

Edited by tsuokun
corrected a wire colour
  • Like 1
  • Thanks 1
  • 7 months later...
On 5/8/2021 at 7:43 PM, tsuokun said:

Split the GRAY with RED stripe wire (+12v) to three places:

Firstly big respect for your writeup, however; I just had an experience that contradicts this.

 

TLDR: Gray/Red exists and affects the dash lights and the switches, however; I ended up not using it at all as it was not needed and caused new issues. Replace Gray/Red with the Gray 12V constant power and above advice worked!



I got the car with auto to manual conversion already performed - it had reverse lights pretty sure, but they stopped working at some point. Never had neutral switch, never had the auto cluster light up with P, N, or R.
My setup:

R34 GTT with R34 box, auto cluster, auto ECU, nistune with a MANUAL base map. Symptoms of no neutral switch are questionable idle AFR's that seemingly cant be tuned out.

 

The original wiring:

Inhibitor (Black/Pink) with constant 12V power (Gray) joined together (correct)

Neutral switch: Green/White (correct) and Yellow/Brown (seemingly incorrect)

Reverse switch: Red (correct) and Black (shared with Speed sensor, presumed earth I forgot if it is, seemingly incorrect, HOWEVER IT WORKED AT SOME POINT - my flimsy guess is changing the base tune map from an auto to a manual caused this).

This wiring as I found it is exactly as directed by a guide on SkylineOwners that always shows up top of google. It does work for some people - seems to require a manual cluster?

 

I found the Gray/Red wire and it blew the A/T fuse once I connected it to enough things. I experimented with countless combinations and at one point I had constant neutral, constant park, and in reverse all three (with lights on). There was another combination that caused the dash to show neutral OFF, but the ECU was reading neutral ON in all gears.

After enough trial and error, I found the pattern and my new wiring that works perfectly (Never shows P, N in neutral, R in reverse, ECU reads neutral position correctly too; reverse lights on when desired, speedo works).

 

GRAY 12V power to Inhibitor (BLACK/PINK)

GRAY 12V power also to reverse switch, other wire RED

GRAY 12V power also to neutral switch, other wire GREEN/WHITE

 

This was the mightiest clusterf**k to figure out (the loom has been absolutely mangled with random colours everywhere changing up along its length with splices) but we got there! I think previous owner had a bad time of it and gave up lol.

 

Please let me know if there absolutely is a purpose to the Gray/Red wire regardless of the fact my setup seems to work now

Edited by CowsWithGuns
extra relevant info and clarity
  • 4 months later...
On 05/01/2022 at 11:34 PM, CowsWithGuns said:

Firstly big respect for your writeup, however; I just had an experience that contradicts this.

 

TLDR: Gray/Red exists and affects the dash lights and the switches, however; I ended up not using it at all as it was not needed and caused new issues. Replace Gray/Red with the Gray 12V constant power and above advice worked!



I got the car with auto to manual conversion already performed - it had reverse lights pretty sure, but they stopped working at some point. Never had neutral switch, never had the auto cluster light up with P, N, or R.
My setup:

R34 GTT with R34 box, auto cluster, auto ECU, nistune with a MANUAL base map. Symptoms of no neutral switch are questionable idle AFR's that seemingly cant be tuned out.

 

The original wiring:

Inhibitor (Black/Pink) with constant 12V power (Gray) joined together (correct)

Neutral switch: Green/White (correct) and Yellow/Brown (seemingly incorrect)

Reverse switch: Red (correct) and Black (shared with Speed sensor, presumed earth I forgot if it is, seemingly incorrect, HOWEVER IT WORKED AT SOME POINT - my flimsy guess is changing the base tune map from an auto to a manual caused this).

This wiring as I found it is exactly as directed by a guide on SkylineOwners that always shows up top of google. It does work for some people - seems to require a manual cluster?

 

I found the Gray/Red wire and it blew the A/T fuse once I connected it to enough things. I experimented with countless combinations and at one point I had constant neutral, constant park, and in reverse all three (with lights on). There was another combination that caused the dash to show neutral OFF, but the ECU was reading neutral ON in all gears.

After enough trial and error, I found the pattern and my new wiring that works perfectly (Never shows P, N in neutral, R in reverse, ECU reads neutral position correctly too; reverse lights on when desired, speedo works).

 

GRAY 12V power to Inhibitor (BLACK/PINK)

GRAY 12V power also to reverse switch, other wire RED

GRAY 12V power also to neutral switch, other wire GREEN/WHITE

 

This was the mightiest clusterf**k to figure out (the loom has been absolutely mangled with random colours everywhere changing up along its length with splices) but we got there! I think previous owner had a bad time of it and gave up lol.

 

Please let me know if there absolutely is a purpose to the Gray/Red wire regardless of the fact my setup seems to work now

This is pretty much where I'm at, this is absolutely doing my head in. Blowing fuses left right and centre. 

 

R34 auto loom, and have the plugs off a R33 manual loom. 

 

Haven't managed to get reverse lights or anything at this stage. Just blowing fuses.

 

Currently running a link g4x PNP ecu 

 

If anyone has pictures that could enlighten me on how this should be setup, figured someone would have updated a write up by 2022 by now haha 

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