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Proud owner of a GA16i
508 Posts
Discussion Starter · #1 ·
Thanks to Webfoot, I have in my posession a used B12 gauge cluster. Today I got my brand new 1990 Sentra FSM. That damn thing is freakin' golden, and tomorrow, I begin the cluster swap! No questions, but if I have any notes, I'll post em here. This swap oughta be fun.

Proud owner of a GA16i
508 Posts
Discussion Starter · #2 ·
Well, I ran a test setup to verify that I was splicing into the correct wire. From the FSM, I spliced wire 3 from the ECU. I then spliced wire 11 for power, and 14 for ground. I rand the wires into the tach gauge which I left on the floor of my car.
The setup on the harness was as follows:
wire 11 -- > 1
wire 14 -- > 4
wire 3 -- > 10
I started the car up, and what do you know? Success on my first shot! The tach works like a charm. I'll try to explain the wiring numbering later (unless everyone knows what I'm talking about), when I write up a full report on the actual wire swaps and post everything here. Now I just have to upload my pics of the setup. . .

501 Posts
Even though your done already I'll post what greg sent me when I asked him the same question... His email is [email protected]

Tachometer Install for Nissan 1987-90 B12 Fanatics!

Tools Needed: #1 Small Flathead Eyeglasses Screwdriver Set.
#2 Wire Stripper Tool.
#3 Ten Feet of 22 Gauge Wire.
#4 Drill.
#5 Firewall Tapping Drill Bit.
#6 Grommet.
#7 Silicone or similar sealing compound.
#8 Electrical Tape.
#9 Pencil & Pen with two sheets of plain 8 ½ x 11 paper.
#10 Box cuter.
#11 Phillips Head screwdriver.
#12 Bucket or basin for storage of screws and other small parts.
#13 Solder Iron and Solder.
#14 10 black zip ties.

Equipment Needed: #1 Tachometer Cluster from 1987-90 Nissan Sentra SE or GXE only.
#2 Both Black wire harness connectors in the back of the cluster.
#3 About two inches of excess wire slack from the harnesses

Time Estimated: Novice 3 hours.
Expert 1 ½ hours.
Pro 1 hour.

Suggestions: Begin and conclude task during daylight hours.
Set favorite radio station.
Have food and drink on hand so you can work uninterrupted.
Wear comfortable clothing.
Concentrate and take your time.
Have extra vehicle ready in case of emergency and you need to suddenly leave.
Once you begin plan not to move this vehicle until you finish.
Use a workbench to place removed items if N/A use back seat for storage of parts.
Put screws in bucket or basin keep it by the drivers door.
You will start and conclude this mostly in the drivers seat.

Step #1 Disconnect negative battery terminal and lower hood.

Step #2 Use Phillips head and unscrew and remove steering column cover halves.

Step #3 Use Phillips head to remove instrument bezel finisher gently pull forward.

Step #4 There are circuit boards behind it unplug them.

Step #5 Use Phillips head to unscrew the cluster gently pull forward and unplug both black harness plugs.

Step #5 Draw a picture of non-tach harness plugs from the head of the plug not the back.

!NOTE! Each wire is a solid color with color bands around it. EXAMPLE purple w/orange bands.
The drawing of the plug harness is where you will note the different wire color codes.
EXAMPLE if it is a 16 plug harness and the upper left plug is where the purple with
Orange band wire is draw a line to this block and write this along the line so you know where that
Wire is NOW. Repeat this with ALL wires on both harnesses FIRST!

Step #6 Look at the back of the non-tach cluster. You will see a maze of copper lines. Start at the plug
In point and track it back until you see a word EXAMPLE fuel. Now you know that this is the line
Plug point for the purple w/orange bands wire and NOW you know this is the fuel level readout
Wire. On your drawing write fuel next to where you wrote purple w/orange bands.
Continue until you have finished both harnesses. Double check yourself for accuracy! Make
Sure you write NON-TACH on ALL non-tach drawing papers because you will be doing this
AGAIN! Make sure you write LEFT PLUG or RIGHT PLUG on each draft you do!

Step #7 Draw a HEAD-ON picture of the TACH harness and write TACH on the paper so you know!
Next look at the back of the tach cluster NOW follow the maze from where the plug plugs in.
EXAMPLE you now see that this particular copper line is the fuel line on the TACH cluster
On your tach drawing draw a line from that sector and write fuel on the line. Repeat this until you
Finish both harness plugs on the TACH drawing. Double check for accuracy!

Step #8 Take all drafts and sit down to re-arrange them on paper and assign a color code to the TACH
Harness drafts. How to do this is. . . Now that you have ALL of the codes written in on the NON
-TACH drawing EXAMPLE fuel, temp, battery, so on. . . You look at the TACH drawing and you
see FUEL. Match it up with the NON-TACH drawing and you see this is the PURPLE wire
with the ORANGE BANDS write it on the proper place on the TACH drawing. Now you know
when you RE-WIRE this harness this is where this particular wire will go! Repeat until you finish
both left and right harness plugs. Double check for accuracy, then head back to the battlefield!!!

Step #9 Grab your eyeglasses screw driver set and get the smallest and the biggest one out. Use the biggest
One to pop open the harness plugs, use the small one to unlock and remove the actual tabs from
The harnesses. START WITH THE TACH HARNESSES FIRST and be GENTLE!!!! Once you
Look at the closely you will understand how to configure your SMALL screw driver to unlock
Them. Once you unlock them GENTLY PULL BACKWARDS and slide each wire out. Each
Wire has it’s individual lock so you have to repeat this until ALL are removed from both
Harnesses. Now that both of the TACH’s harness plugs are empty they are ready sit them on
The square shaped indentation on the top center of the dash. You will need to get one out in
Tact and you will it is not that delicate of a procedure.

Step #10 The same POP-OUT procedure you had done on the TACH harness plugs and got some practice
In too! NOW hotshot, try it again on the ones popping out in your face. The NON-TACH harness.
You must get these out too. Phew, done. Now all you should have is wires! YOU HAVE TO BE
THEM INTO A NEW HARNESS PLUG!!! Still sitting in the car put the TACH cluster on your
Lap. Put the drawings of the TACH ONLY on your dashboard too. The best way to do it is to just
Take each wire as it comes to you. Identify the solid and the banded color on your drawing, next
Take your TACH cluster and follow the maze to find where it contacts on the copper patch thing,
Now take the harness plug for the tach cluster and connect it to the proper slot! Like Emril Live
“BAM” you got it! Left plug will ONLY fit the left socket, right plug will ONLY fit the right
socket. Double check every move you make before you make it at this time so that you get it
right the first time. Now that you have finished re-wiring the harness plugs this is a good time to
replace any burned out LOOKING bulbs in the cluster and set the miles of the new cluster to
the actual miles of your car. I cannot type you through this one, you will have to mail me
your cluster and I will set it for you.

Step #11 Get your eyeglasses third from the tiny one and grab one of those old cut-off wires from the
TACH-HARNESS that you popped out earlier. Gently pry open the clasps that hold the wire to
The lead. You are going to preserve the lead because you are going to re-use it NOW! Once you
Pry it open the end has a dot of solder on it just cut the wire here, BUT PRESERVE THE LEAD!
Heat up your solder gun and grab that 10 foot 22 gauge wire. Strip one end and slide it in the old
Wires place and clasp it, last put a dot of solder on the middle portion to give it that O.E. touch!

501 Posts
Step #12 Grab your drill, silicone, grommet, and bit. Tap a hole in your firewall close to the left side
Because you want to get this to come out in the engine bay as close to the O.E. wire line as
Possible. Put your grommet in place. NOW find on your TACH drawing where it says TACH
And plug the wires lead into this slot. Now fish the excess down into and behind the instrument
Neatly run this wire in through and around from danger and pass it through the grommet hole

Step #13 Now plug in TACH harness to cluster and RE-CONNECT negative battery cable put key in and
Turn on car NOT MOTOR. You want to check to see all things work at this time. Once you see
Everything works, DISCONNECT NEGATIVE TERMINAL and lower hood. Turn signals and
Hazard flashers will NOT work unless the circuit board is in do not worry this is fine now.

Step #14 Re-assemble everything back to the way it was, you are in the home stretch!

Step #15 Now GENTLY tighten up the tach wire and pump silicone through the grommet to seal it
And keep water from getting in through the little hole. Use your zip ties to secure the tach
Wire as you route it away from being caught or pulled or you may use your electrical tape.

Step #16 I cannot tell you where to connect the tach wire because I do not know what that thing is
Called but I do know where to connect it and I can mail you a picture of where to connect it
And point to the thing you connect it to and you will see it on your car and then you will
Know. This is where the manufacture would connect it not some good spot I found, I did
Consult a Nissan Certified mechanic and he did tell me where this goes so you have the best
Most accurate information possible. NO you do not connect it to ANY part of the distributor.
Incorrect or improper connection will result in TACH failure and your time will be worthless!

Step #17 Neat and clean make it look factory use that roll of electrical tape and go around the tach lead
AFTER it is trimmed and secured to it’s resistor. You may need to request the picture of it from
Me. You want the tach wire to be secured to the cars O.E. wire loom, remember it’s got to look
STOCK! Neat & Clean is the way I like it! Re-connect your negative cable, close your hood,
Sit in the driver’s seat, close your door, REDUCE your heart rate, put the key in and B-A-M!!!
WATCH THAT TACH RISE UP, IT’s ALIVE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 
I had all of the wire colors and pictorials before but I cannot find them so you will have to make
Your own. This will help you call me I want you to be successful I will guide you through this.

Once again thanks to Greg. I did not write this just passing on the valuable information..

Thanks Greg

Proud owner of a GA16i
508 Posts
Discussion Starter · #6 · (Edited)
Webfoot said:
Good Job:cheers: Did you only have to change only 3 wires? Was my Tacho Mania page help?

I have another tach and harness to sell.
No the three wire splice was a check to make sure I have the right wires that go to the tach. Surprisingly they were. As for the rest of the swap, everything went in smoothly, except for two things
1) the brake light is always on
2) speedometer seems off (it reads 55 mph when I'm only going 25)

As for the tach pics, sorry, no, the spaghetti hurt my eyes :cool:

I may have mislabeled and switched two wires. I'll get on it tomorrow.

Proud owner of a GA16i
508 Posts
Discussion Starter · #7 ·
minute rice sentra said:
Just wondering, does the GXE sedan cluster and the sport coupe cluster have the same type of connectors on the back?
FSM only showed two different clusters for the 90 sentra, with and without tach, and the 2 connectors were the same on both.

off topic VIP
388 Posts
this thread should be a sticky. i have finished my GA16i tach swap, and i have these things to add to this valuable thread:

at the coil, u must Tap into the white/red stripe wire . this is located at the beige resistor u uncover after unwrapping the electrical tape around the wiring leading to the connectors at the coil. look for a lightening symbol on the resistor.

route the tach wire through the drivers inner fender. fish tape helps get the wire through.

for this project, u need the FSM for gauge information. i have the FSM, and will gladly send u a scanned copy of the 2 pages u will need.

about the wiring at the cluster:

u will assign each wire a new location in the new connectors, as directed by the FSM. after u relocate each wire to its new slot in one of the 2 connectors, u will find when u r done u have 2 wires left over to transfer. do not panic.

the yellow ign wire from the original cluster is not used in the new cluster.

the black ground left over must be placed on the new cluster where it is needed. simply look where u have a contact on the cluster for a needed ground, and slot the ground into the respective connector slot.
also leave the tach slot in the connectors blank.

the illumination in the new cluster has 1 more light, so u will need to piggyback from the tach ill+ and ill- its pretty easy to understand. the FSM will direct u to wire the tach for lights, but u will need to piggyback the + and - to the speedo side. easy stuff.

btw u can re-use your old speedo unit in the new cluster! again straight forward. u already have precision screwdrivers, so get the phillips one for this part of the project.

begin by pulling the speedo needle off the new cluster. hold the wheel in the back of the speedo unit firmly, as u pull. dont just yank on it without supporting the delicate wheel in the back!!!! next remove the 2 screws holding the speedo on. the speedo will come off. repeat the process on your old cluster, and put your old speedo on the new cluster. after u install your old speedo on the new gauge face, BE SURE TO MAKE SURE THE NEEDLE RETURNS TO ZERO QUICKLY or it will be inaccurate. wind the spring for the needle by holding the wheel in the back and moving the needle in the opposite direction. straight forward stuff.

btw dont rush this project, and it will not take u 3 fucking hours if u want factory perfection. relax, have food on hand, and have a spare vehicle. this project took me a very casual week to complete. if u rush yourself through this, u will make a mistake.

one last thing: when testing, u will find the blinkers dont work. there will be no continuity unltil u CONNECT THE HAZARD SWITCH.

my project went off without a hitch, and i hope this writeup benefits someone.

18 Posts
i just finished doing this yesterday night and looking back it wasnt hard at all. but looking at all the posts on here confused me alot more then it should have. once i stopped thinking about it so much and just did it, it was really easy. the hardest part about it is getting all the wires out of the plastic plugs.
this is a drawling i made of what the plugs look like stock and what it should look like after your done swaping and splicing.

basically you just swap the wire from the old non tack harness to the new one in the right order. the way i ended up doing it was going back to the junk yard and cutting another tach harness out and using it as reference. but hopefully the pic i drew will eliminate the need for others to do that. one tip i have for you is to take some masking tape and lable each wire with a number in the stock plug going left to right so if you for some reasion need to put the non tack gagues back in, you know what wire goes where.
one other thig i did was i took the tach gages apart and took out the green bulb covers. it made the gauges alot brighter and alot eaiser to read at night.

Proud owner of a GA16i
508 Posts
Discussion Starter · #10 · (Edited)
OK, I apologize for being a retard/asstard for saying I'm going to do the cluster swap, doing the cluster swap, and not documenting it fully here. So, to remedy that, I will now spew the notes that have led me to a successful cluster swap. Hopefully, they make sense. First off, some pics:

Wiring for gauge cluster with tach:

Wiring for gauge cluster without tach:

Studying the two clusters, you'll notice that the wiring is extremely similar, with the gauge cluster w/tach having 2 extra wires (tach signal from ignition coil or ECCS Control Unit, 2 extra illumination wires, but one less ground). one of the connectors fit on both clusters, but I recommend that you have the tach cluster connectors on hand (unless, of course, you're fearless swapping wires, or a really good electrical tech).
In your car, disconnect the battery (more to protect the ECU than anything else), and take out the gauge cluster. Take some time and study the wire locations. The FSM pages I scanned clearly mark out which wires are which. Now, unless I made a mistake, the wiring is as follows:

no tach loc.........tach loc.........instrument
......10....------......19.............hi beam indicator
......17....------......22.............hi beam indicator
......2......------......5..............e brake indicator
......1......------......23............oil dummy indicator
......18....------.......3.............charge indicator
......9......------......13............CEL indicator
.....6,14...------......4..............ground belt indicator belt indicator
......7......------......11..............LH turn
......8......------......12..............RH turn
......12.....------.......6.............fuel gauge
......13.....------......14............H2O temp gauge
......21.....------......24............Vehicle Speed Sensor
......20.....------......18............Vehicle Speed Sensor
..............------......10............tachometer signal

The crap above reads as follows: ex. first line - the wire in pin location #5 located on the connector in EL-57, on the cluster without the tach, is an illumination wire. It must be split and put into pin locations #8 and 20 on the connectors in EL-56, on the cluster with the tach. Its as simple at that.

I don't have the wire colors, but there is a diagram about that in the swap how-to sticky. (if merged, umm, NVM) Now berore you go swapping wires, it is fairly imperative that you have each wire marked/tagged. Now when you are ready to start swapping wires, you'll need a very small flat head screwdriver (one of those mini ones from a basic computer tool kit are perfect) and about 5 feet of, I don't remember, I think 12 or 14 gauge wire, and a solder gun with solder.

Remove the black instrument cover, its held on the dash by 7 screws - 3 on top, and 4 on the bottom. Once the screws are removed, work the cover off about 3 inches, enough to reach behind the cover and disconnect the hazard light button, the rear defogger button, and the "i forgot what it is" stuff/lights on the left. Remove the gauge cluster by removing the 4 screws holding the cluster down. Then pull the cluster about 5 inches back, enough to reach behind the cluster and disconnect the 2 connectors. Pinch the middle of the connector to remove it. Each connector has 2 tabs that can be bent back out of the way. Carefully shove the screwdriver into the back of the connector, using it to wedge the wire loose from the connector. A little study and some manual dextreity and practice, and you should be able to pop out the wire with no problems. Take the wire from the no-tach connector to the new tach connector and line it up to its new pin location. slide the wire in, and it should click into place. If you have to splice wires, say the illumination wire, take about 6 to 8 inches of the extra wire I told you to have. twist it around the wire you want to splice. Then take that wire and put it into one of the new locations. Take the other end of the splice, and put it into the other new location.

EX: remove the wire located at no-tach pin #5. Take the 6 in. of 12 gauge wire and wrap on end around this wire. Install this wire into tach pin #8. Install the other end of the 6 in. wire into tach pin #21. This is done by sticking the wire through the connector and then bending it back over the connector. If you need pics, I'll throw them up later.

The final wire is the tach signal wire. It is found by tracing it from here:

Good luck, its on the left, by the power transistor, hope you can trace it.

LOL, j/k the tach signal can be traced either from the inside of the cabin, or inside the engine bay. The easy way is from inside the cabin. Locate wire #3 on the ECU. It is located on the 12 pin connector. Wire #3 is red with a white strip. Splice into this wire, run it up to the gauge cluster, and install it into pin #10 on the tach connector.

The hard, but clean way is to locate the red wire with a white strip on the 2.2 kohm resistor & condenser relay. Splice into that wire, run it through the firewall, and install into pin #10.

If you want to splice directly into the ignition coil, good luck, you're on your own.

Put everything back together, start up the car, and check all the instruments for correct function. This set of notes is as thorough as I got on this project. Hope this helps anyone thinking of the swap. LONG LIVE THE B12!!!!!!!!!!

Proud owner of a GA16i
508 Posts
Discussion Starter · #11 ·
OK, a little change in the wiring. . .

pin #11 no tach = pin #1,16 tach = power

pin #6,14 no tach = pin #4 tach = ground, common, return, etc. . .

pin # 10 tach = tachometer signal.

If you wanted to check that you have the right wires, these three are the only three you need to connect to your tach cluster to check if the tachometer works. connect those three wires, start up the car, and your tachometer should work. If the tachometer doesn't work at this point, put everything back together, and study up on the wiring diagrams some more.

It took me about 2 hours to study the FSM and sort out the wiring diagrams. Another 1 1/2 hrs. to do the install. I ended up swapping 2 wires incorrectly, and spending a little more time trouble shooting.

Ex-mod/nissan guru
2,136 Posts
Here it is !!... everything you always needed to do the swap. in plenty of diagrams to help you out... if still you got some problem or questions regarding the swap : it might be to harsh for your skill !! then reread the thread or DONT DO IT !
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