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Old 05-26-2012, 12:15 AM   #1
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Default NB Auto to Manual Swap - How to wire up speedo, reverse lights, and neutral switch

I'm adding this thread with info I obtained from other sources and my own personal recent experience swapping a manual transmission into my 99 auto. It was difficult to come across clear and useful information on this wiring. This is here strictly for the next guy who is searching for this info.

This pertains to the 1999 and 2000 NB


There are numerous tutorials out there that tell you what you need to do the 5-speed swap but not a lot of help with wiring. A few tips: you definitely need the ECU, the driveshaft (completely different) and the powerplant frame(several inches longer than the auto version). You also need all the obvious mechanical and hydraulic parts, including the brake pedal. (it can be swapped easier than swapping the entire assembly)

You don't need a manual wiring harness to do this. The manual computer plugs right in. The automatic transmission control unit will be removed, but you will jump some wires into the connecter where it used to be.

These steps follow the installation of the transmission and everything else:

Neutral Safety Switch

This one is easy. Find the large connector that used to hook to the side of the auto tranny. Cut all of the wires off the connector close to the ends. (to spare as much wire as possible to work with)

There are two heavy gauge wires - Black with Blue Stripe and Black with Red Stripe. These can simply be spliced together and the car will start. You can also tie these into the two small single wire white plugs coming off the top of the tranny. That will require the car to be in neutral to start. There is no polarity to worry about, as it is just a switch. I spliced the two wires together so it will turn over no matter if you're in neutral or holding the clutch or anything. (if you're prone to momentary acts of stupidity, you might want to hook the switch up)


Reverse Lights

The other connector coming off the manual tranny that has two conductors and close to the neutral safety switch is the reverse lights switch. Cut off the connector and spare as much wire as possible. (cut close to the connector itself)

On the same large auto connector you found the neutral wires - look for the Red with Yellow and Black with Yellow wires. Splice these together with the two wires from the small connector you just cut off. Again, polarity is not an issue.



Speedometer

Now this one is a little tricky. You need the speedo sensor that comes with the manual transmission. Make sure you get a tranny that has all the sensors plugged into it. (or get all these to go with it)

I hacked the connector off of mine and tied it into the Yellow and Orange wires from where the auto speedo plugged into. (one of the dangling connectors has yellow and orange wires, pretty easy to locate) I did not pay attention to polarity and I'm not sure it matters. Mine worked on the first try. If yours doesn't, you could try swapping the two wires - but my best guess is it doesn't matter.

Pull your gauge cluster out of the dash. (yes, your gauge cluster) This requires removing the steering column cowl (three phillips screws from underneath - then separate upper and lower halves) - Then pull the gauge hood off the dash. It pulls straight back toward you and pops off. Now there are four phillips screws surrounding the cluster. Remove these, and you're there.

Turn the gauge cluster to point the gauges up. You'll find three connectors on the back. The larger white one on the left needs to be unplugged.

You will find an empty slot for a pin between the White with red stripe and the black with some sort of stripe (purplish or reddish) It's the fourth position on the connector. You need to insert a pin here if you can get one or do what I did - use a solid core wire and fold it back a little so it will work as a pin and make contact with the cluster flex circuit. Just be sure it sticks out a little with some pressure applied to it and you should be good.

Run that wire down behind the dash with the harness. Make sure it's long enough to reach near the fuse box (leave some extra to play with)

You should have the auto ECU removed and the manual ECU in its place. The auto tranny controller is the small unit next to it. That also needs to come out. You will be connecting the wire you just added into that plug where you see the Yellow wire. I used the solid core wire and wrapped around the connector once, then pressed it in. Mine is held in place with a ziptie.

Lastly, jumper together the Orange wire and Black with White Stripe wire. They sit right next to the Yellow wire from the previous step. I also held this wire in with a ziptie.

Now everything should work. My speedo operates correctly, but I haven't checked calibration. I don't know which speedo sensor I have. My check engine light hasn't come back since I reset the ECU, either.


EDIT: Update: Speedometer is working perfectly. I checked it against the SpeedView GPS app on my android phone. It's within 1mph all the time, it seems. Tested at 25mph, 40mph and 60mph. That's accurate enough for me.

Check engine light has not shown itself, either! This was a complete success.

Total cost for this job was around $2000 using a lot of aftermarket parts. Could be done for much less using OEM junkyard parts and doing all the labor yourself. Consider that when deciding to swap your auto or sell/buy a new one with a 5-speed. Resale on the autos is so low... it might not work out with all the hassle of changing cars. I'm very happy with mine now.

Last edited by Hugh; 06-01-2012 at 12:40 PM.
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Old 08-12-2012, 09:04 PM   #2
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Originally Posted by Hugh View Post
You will find an empty slot for a pin between the White with red stripe and the black with some sort of stripe (purplish or reddish) It's the fourth position on the connector. You need to insert a pin here if you can get one or do what I did - use a solid core wire and fold it back a little so it will work as a pin and make contact with the cluster flex circuit. Just be sure it sticks out a little with some pressure applied to it and you should be good.

Run that wire down behind the dash with the harness. Make sure it's long enough to reach near the fuse box (leave some extra to play with)

You should have the auto ECU removed and the manual ECU in its place. The auto tranny controller is the small unit next to it. That also needs to come out. You will be connecting the wire you just added into that plug where you see the Yellow wire. I used the solid core wire and wrapped around the connector once, then pressed it in. Mine is held in place with a ziptie.

Lastly, jumper together the Orange wire and Black with White Stripe wire. They sit right next to the Yellow wire from the previous step. I also held this wire in with a ziptie.

Now everything should work. My speedo operates correctly, but I haven't checked calibration. I don't know which speedo sensor I have. My check engine light hasn't come back since I reset the ECU, either.
question! i have done all this but... my speedo still isn't working. i hooked up the wires as said... but now my tach jumps up and down when i'm going slow and it slowly starts to fade away as i speed up. my odo counts now. not sure if it's acurate. it turns off at a certain speed. it's like my dash is powered by the + signal from the sine wave. any help?
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Old 08-13-2012, 04:43 PM   #3
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Originally Posted by sledgods View Post
question! i have done all this but... my speedo still isn't working. i hooked up the wires as said... but now my tach jumps up and down when i'm going slow and it slowly starts to fade away as i speed up. my odo counts now. not sure if it's acurate. it turns off at a certain speed. it's like my dash is powered by the + signal from the sine wave. any help?
If your tach is bouncing, you've done something wrong. Retrace every connection as I explained and also make sure the connectors are all plugged in properly when you put it back in the dash. (might have a loose connection on the cluster)
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Old 08-20-2012, 09:00 AM   #4
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Just bought this very nice '00 NB for $2300 - nothing wrong except it being an auto - just saying thanks for this write-up it'll save me some time and headaches and lucky me, I have almost everything to do the swap - other than speedo sensor. Next step - loose the rims and get an affordable street suspension.



Last edited by GeneSplicer; 08-20-2012 at 09:12 AM.
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Old 08-20-2012, 04:18 PM   #5
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Nice looking car (minus the chrome)

It will be far better with a stick in it. I'm so happy I finally swapped this one over.

Everything is still working great a few months later.
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