How to: Install Aftermarket Tach

I couldnt find a good write up on how to install an aftermarket tach so I decided to make one to help out others who want to do this

Tools required:
Wire cutters
Wire strippers
Philips screwdriver
Flathead screwdriver
10mm and 12mm socket with ratchet
Soldering iron/gun
Solder
Electrical tape



Disconnect your ground wire to the battery with your 12mm socket!

WRAP EACH SOLDER CONNECTION AND CUT END OF EACH WIRE IN ELECTRICAL TAPE.

Mount your tach wherever you want. I used these velcro strips from target that were 3 dollars because i didnt want to drill into my dash.

We need to pull out the instrument cluster to do this, so first we are gonna need to take off the trim piece surrounding the a/c controls and radio.



Start by removing the knobs from the climate control. They pull right off.



Next take your flathead and pop it out.



There are 2 screws holding it into the dash. This is the one on the right, and then you need to remove the one on the left. There are little clips holding it in after you remove the screws. They will come right out with a little effort with a flathead and disconnect the hazards switch.




Next your gonna remove the piece under the steering wheel. It has 4 bolts holding it in. 2 on the left, 2 on the right. I had already taken it off, but you get the point




Pry out the piece around the ignition, it has 2 clips holding it.




Now remove the trim around the cluster. Remove the screws holding it in. I didnt get a picture of all of them but dont forget these 2..




And you know the drill... pop it out with the flathead. The drivers a/c vent kind of gave me a problem but it came out after some tugging.




Then we can finally remove the instrument cluster. Remove the 4 screws around it.




Unplug all the harnesses hooking up to the cluster. It will come right out after you remove the screws and harnesses. Disregard the green wire in this picture, my tach was already installed but i used wire nuts instead of solder.




This is where your going to connect the green wire on your tach. Use the PLAIN black wire going to the blue harness. Cut it, strip it, and solder the 2 cut ends and the green wire from the tach together.




Now we need to connect the tach to a power source. I used the clock harness for this. Some tachs may draw too much power for this to work but mine is only a 3 inch backlit with no shift light. So its fine for me.

Unplug the harness from the clock, this is what it looks like.




Cut and strip the grey/red wire on the clock harness. This is what you will solder the positive wire from the tach to.




Cut and strip the yellow/black wire on the harness. The negative wire from the tach solders onto this one.




And the last one.. cut/strip the green/red wire on the harness. Your illumination wire from the tach will solder onto this one. On my tach it was the white wire, pretty sure its the same for all of them.


I took all my wires and used zipties to coil them all together like a hose so they werent all over the place. You could drill holes behind the tach to run the wires thru but i didnt want to ruin the dash.

Put the cluster back in, and hook up all the harnesses again. It was a little diffucult to get them all hooked back up but its not impossible. Before putting everything back together check that its all working still. Make sure your tach is plugged in. Reconnect the ground wire on the battery. Start it up and check if its working. Make sure your tach is set for the correct number of cylinders. You can search for the manual on google if you dont have it to find out how to change the cylinder setting.

If its not working, check all your connections and make sure theyre secure. While putting everything back together, make sure to plug everything back in.. for example the clutch start cancel, the dimmer knob, your hazards switch, etc.

And heres your finished product:


If you have any questions pm me!

Thanks! Enjoy!

 

This method didn't work for me. You must need to have an instrument cluster that already has a tach in it for the wire you specified to get a signal. I ended up following Autometer's recommendation, tying into the black wire coming off the #8 pin on the ignition ignitor harness.



Of course that means you have to run the wire though the firewall, but it turned out to be a heck of a lot easier than pulling the instrument cluster.

Autometer tach of ridiculous size FTW!

 

so you have two tachs now?....

 

The OP does, apparently. I didn't have an instrument cluster with a factory tach so I had to install my own.

 

What's the need for more than one? Because race car?

 

Maybe his OEM tach quit working?

 

my 97 doesn't have a tach either that's why i bought my scangauge. i like where you put your tach baka looks good.

 

Thanks. I thought about putting it where the OP did, but I was worried it would rattle on the windshield so I went with the A-pillar. Worked out better there any how. Doesn't obstruct the view out over the hood, doesn't rattle on anything, and it's easy to see. Oh, and it didn't require putting holes in anything to run the wires, but the wires are still mostly hidden for a clean installation.

I may eventually get a Scangauge, but I had this tach taking up space in my toolbox, so I figured I might as well use it. Next up is installing a mechanical oil pressure gauge. That could take a while since I need to figure out the correct fitting I need to still be able to have the factory oil pressure sensor functional to avoid idiot lights on the dash while also having a tap for the 1/8" copper tubing for the gauge.

 

Where did you run the wire for power to the tach on that one without a tach in the the cluster. And where did you find the ignition igniter?

 

I pulled power from one of the wires going to the ignition (starter) switch that was hot when the key was 'on'. The ignition igniter is located on the passenger side fender well (in a 1st gen).

Good luck with it.

 

First thanks to the OP for the clock idea, that made this super easy. Second the OP soldering job needs some work, a few online tutorials would help. heat shrink tubing and proper soldering would make this look professional. I didn't cut any wires, just stripped about 1/3" section and twisted tach wire, soldered all connections, and removed pin from plug to slide heat shrink tubing in.

On my 98, I pulled power and light power from the clock hardness just like the OP, I routed ground to the left wall under dash, but just like OP there's a ground on the clock and that should also work. I tapped the signal from the ECU behind glove box.

All you need to take apart is glove box, and lower dash under driver. ease and sweet.

 

Is this junction box on the passenger kick wall area inside the truck or under the hood area on the passenger side?

 

It's on the top side of the passenger wheel well, under the hood.

 

thanks a ton for the post on the installation. helped out a lot.