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extremely simple FD tach/ odometer repair

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Old 01-24-14, 08:32 AM
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extremely simple FD tach/ odometer repair

So, i know a ton of people have issues with tachometer and odometer issues with their clusters, so i figured i would post a couple things that i have discovered over the course of building my FD. Hopefully this is helpful for people searching, as i did, for cluster issues.

So when i first put a battery in the car to begin testing all the electronics, i noticed that the gauges all worked except for the speedometer and odometer. I began searching, and found on ebay a cluster that all worked except the tach. I figured perfect, i'll get this, put my working tach in, and be done with it.

I got the cluster, put my tach in, put the cluster in, and still no working tach. I put the "non-working" tach from the new cluster in the old cluster, and it worked. So i realized the tach not working is not the tach itself, but the cluster.

After some research and inspection of the cluster, i realized the 3 mounting screws that hold the tach to the cluster are also the way in which the tach gets electrically connected to the circuit board. After some testing with a meter and research, i found that the top screw is ground, the right screw is signal, and the left screw is +12v. So i tapped off the signal wire from the cluster harness (right before the connector to the cluster) and ran it right to the screw, fired up the car, and the tach in the new cluster now worked.

So if you have a tach that doesnt work, try jumping the signal wire (Yellow / blue wire from connector 3, i think) to the right tach mounting screw


Fast forward a few months, and i find someone selling a cluster for dirt cheap cause the tach and speedometer / odometer dont work. I pick it up thinking the tach probably does work. I plug it in, then hook my jumper wire from my signal to the right screw, and still nothing. I check the other 2 screws with my meter, and find that the left screw does not have 12v. I add another jumper wire from the cluster connector (black / yellow, i think) to the left screw. Start the car, and the tach works, but to my surprise, the odometer is now working as well!

Moral of the story, if you have a cluster with tachometer / odometer issues, before thinking it is junk, try running a +12v, ground, and tach signal wire to the mounting screws



hope this helps some people out and saves some money!
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Old 01-26-14, 05:05 PM
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can you show a picture how you did it?
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Old 01-27-14, 10:08 AM
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Originally Posted by rx7socal View Post
can you show a picture how you did it?
ill take a pic when i get a chance, its really pretty simple, though.

just run a wire right to the screws using a ring terminal.
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Old 01-27-14, 12:50 PM
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Originally Posted by jeffp View Post

ill take a pic when i get a chance, its really pretty simple, though.

just run a wire right to the screws using a ring terminal.
Where did you tap it into?
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Old 01-30-14, 10:30 PM
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Grounding and 12 ddn't work for me. I replaced the caps again and it worked again.well see how long Wil this last.lol.
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Old 01-31-14, 04:39 PM
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This is good. I ended up replacing my cluster because of the tack. Thankfully I kept my old cluster so when my current one dies I'll have some room to play with
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Old 01-31-14, 04:46 PM
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Try to replace the sheet behind the cluster too. Iv done some comparison the usdm has some extra resistors behind the sheet than the jdm version.
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Old 01-31-14, 04:57 PM
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Old 04-18-14, 08:45 AM
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I am having a problem with the tach not working properly. It only goes up to 1500 rpms and the warning buzzer is constantly going. This is a new problem the car has been sitting for 3 months and never did this before. Has anyone had this happen before? I am taking this car to Carlisle to sell and have less than a week to finish it up so any help would be greatly appreciated.
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Old 07-24-14, 06:59 PM
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Thanks man. I've been chasing this gremlin on-and-off for over a year now. I did the "solder fix" then the "cap replacement" then the "tach swap" and was searching for a new cluster when I came across this. 20 minutes and 10 cents worth of wire to jumper from the cluster-connector directly to the signal screw... and bam! It effin worked...

Thanks again.

-Josh
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Old 08-02-14, 03:41 AM
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Tried this and worked wonderfully. Jumped all 3 but was 12v that fixed it for me.
Thanks for the write up!
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Old 08-16-14, 09:14 AM
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I've had cluster issues, and for one of mine the wire inside the needle motor where it goes from the winding to the area where the wire goes to the plastic and then solder points broke loose, inside the motor. The wires are so fine, it's almost impossible to fix. After getting a JDM Cluster and wrestling with that thing for a while, I had a set of Revolution gauges put in by a competent automotive electrician, and it's pretty close to OEM, as far a ornage glow and black back plate goes.

Link:
About Our Revolution Gauges

I'll try and post some pictures of the install tonight.
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Old 08-19-14, 08:46 AM
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Will definitely be trying this! I've has tach issues for a while now... Hope this works for me!
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Old 08-19-14, 09:53 AM
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Anyone have a picture of what wires go to which screw on the connector?
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Old 10-01-14, 08:32 AM
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FYI My odometer recently stopped working but everything else in my cluster works fine. i tried this:

1. jumping the signal wire (Yellow / blue wire from connector 3, i think) to the right tach mounting screw
2. jumper wire from the cluster connector (black / yellow, i think) to the left screw.

but the odometer still doesn't work. i was hoping this would be the be-all-end-all of cluster gauge fixes...unfortunately, it's not...at least for me.
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Old 10-04-14, 01:07 PM
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I ended up taking apart my cluster and found a bad capacitor on my speedometer/odometer cluster. I replaced the bad capacitor and the odometer started working again. i guess the moral of the story for me is check for bad capacitors first and if there's nothing burned out, try hooking up the jump trick outlined in this thread.
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Old 10-10-14, 06:50 PM
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Can anyone confirm which coloured wire I'm looking for in order to get my tach to work properly. Mine seems to dance around a bit by 500-750rpm.

Thanks for your help I hope this is all I need to do!
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Old 10-13-14, 06:49 PM
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After replacing caps and resolding everything including the surface mounted chips under the display, my issue ended up being a bad ground. This write-up was the only reason mine is working now! Thanks from a new FD owner!
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Old 01-11-15, 09:30 PM
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First thing I am going to try on the dodgy gauges in my first FD.

Thanks for posting your results.
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Old 02-14-15, 12:56 AM
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Thanks for posting this!
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Old 06-24-16, 12:41 AM
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Help finding which wires to use please

I tried connecting blue yellow (3f) to the signal screw connection.

Thus made my tach not move at all while driving when previously it would work up to 2500 and then hit or miss from there on.

https://goo.gl/images/ZKOezj
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Old 06-28-16, 01:36 PM
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can anyone confirm the colors of tach signal and 12v please
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Old 06-28-16, 01:55 PM
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Originally Posted by alsxe10 View Post
can anyone confirm the colors of tach signal and 12v please
I still haven't fixed mine but I will share what I have learned. (quick summary: pos and neg can come from the ash tray wire, I still don't know about the signal wire).

I read that the +12v that people use commonly is the ash tray light red wire. It is always on and and the light doesn't draw much.

I found a ground! But using it may be the cause of my tach and speedometer only working when the headlights are on..lol. I took a voltmeter on dc mode and did the following: Plugged the positive end into the key light that is always on. I then took the negative lead and poked a black wire. It then showed 12v meaning that it was a negative which is good. This wire is shown on the attached terminal diagram as 2D (Black/Yellow) but I do not suggest it since it only works when the headlights are on. Just take the ground from the ash tray light, that should work. You will need a fairly long wire to do so.

The tach wire has me puzzled. Using the beeper resistance setting on my voltmeter, I touched the signal screw to all of the terminals on the printed circuit but nothing showed a connection. 3F which is Yellow/Blue shows TAM by it which meant to me that it was the tachometer terminal. I must be wrong since having that jumped to the screw caused a constant beeeeep and the tach did not work at all.

I used automotive splicers which do not require you to strip the original wire at all.

Help anyone on the tach signal wire??
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extremely simple FD tach/ odometer repair-terminals.jpg  
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Old 06-28-16, 05:16 PM
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hmm weird, I've just tried the connectors seems like I am getting no signals, i've got 12v and the ground is good. I've tapped into the yellow with blue wire but there arent any signals
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Old 06-29-16, 01:05 PM
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Speedo has now stopped working as of this morning...
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