Tach in orange cluster not working

[perucho]

So I got an orange number gauge cluster with tach for my 92 GL and the tach is not working. From a couple searches I found that there should be a yellow/green wire that goes from the cluster to the negative side of the ignition coil. My car, although it doesn't have a heated rear window, has the wiring for the rear defroster switch at the dash. Looking under the hood, there are a yellow/green wire connected to the coil and one unplugged and with nowhere to plug it. Look at these photos:

This is the plug with the wire connected to the coil:


And this is the one just next to the coil:


Is that loose yellow/green wire with the small plug the one that needs to go to the negative side of the coil? And which is the negative side of the coil?? Any help would be greatly appreciated. Thanks

[GenevaDirt]

tach is plug and play on a 92....some of the older 88-89 cars were not wired for tachs....but I have never heard of a 90's that was not.

[perucho]

Well, it's plugged but not playing. Should that yellow/green wire with the smaller plug be plugged somewhere?

[GenevaDirt]

not that I know of but not sure....some one will chime in soon I am sure.

[perucho]

I looked at this a bit closer today. The white plug at the coil has two wires: a black/white one and a yellow/green one. Obviously those are the positive and negative connections respectively. I'm assuming that the smaller plug that is loose with the yellow/green wire takes the signal to the tach.
Unless someone else has a better idea, I'm going to connect it to the yellow/green wire at the coil and see what happens.

[wybnrml]

I don't think that is the plug for it,because i just looked on mine and that green/yellow plug by itself is not pluged in and my tach still works.

[perucho]

I don't think that is the plug for it,because i just looked on mine and that green/yellow plug by itself is not pluged in and my tach still works.

Is there another yellow/green wire connected to your coil? I'm going to remove the cluster and make sure the black plug has the yellow/green wire. Thanks for your input!

[wybnrml]

Yeah, there is another green/yellow wire to my coil along with another wire, so there are two wires running to my coil.

[perucho]

Yeah, there is another green/yellow wire to my coil along with another wire, so there are two wires running to my coil.

I wonder if my car just doesn't have it. Do you have a picture of your coil? Thanks!

[wybnrml]

That white plug towards the top of the photo is the other green/yellow plug, but the coil has a green/yellow, and a wire that is black/brownish or maybe white

[perucho]

[ATTACH]2190[/ATTACH] That white plug towards the top of the photo is the other green/yellow plug, but the coil has a green/yellow, and a wire that is black/brownish or maybe white

Thanks. Mine has the same plug. Two wires Y/G and B/W. I removed the cluster and the black plug on the left side does have the Y/G wire. Looked behind the cluster and there is a screw missing. It happens to be connected with the pin for the Y/G wire and the screw location says IGN-. I'm going to try and find a screw this size and report any progress. Thanks for the help. Here's the cluster photo:

[perucho]

That was it! Installed a new screw and the tach works! Thanks for the help.

[MONSOON]

Well its good that you got it working. I wonder why the screw was missing.

[doylerl]

I am wondering if someone had it hooked up to a car with no tach wire, and instead of modifying the plug, they just ran a wire to the screw. Just my thoughts...

[perucho]

I am wondering if someone had it hooked up to a car with no tach wire, and instead of modifying the plug, they just ran a wire to the screw. Just my thoughts...

I bet that's what it was. So for you guys out there that want to install a tach and your black dash plug is not wired for it, you just need to connect a wore from the negative side of your coil (yellow/green wire) to the screw labeled IGN- on the gauge cluster.