Installing a tachometer in a 1998 Toyota Tacoma Pickup

I'm visiting with my friends Josh and James one night. Josh pulls out a Sunpro Super Tach II and says "Let's install this in my truck". So with vague instructions, we set forth to install this tach.

Step 1: Find a place to put it. The tach did come with a mounting bracket, but that would be too easy. We wanted to rip something apart. So we found a blank black section near the ignition, that appeared would allow us to put the tach:

Step 1: The blank panel

Having found this panel, we would later would determine that an optional clock could go in this spot. This would come back into play later.

Step 2: Remove as much as the dash as needed to get the piece out...so we can drill it. I'm not going to go into details on how we got the dash off (your maintenance manual should be able to help you). The key is, we got the piece off. Upon measuring the dial, we used a 2.5" hole saw to drill the piece and install the tach. We used a piece of foam and a pipe clamp to secure the tach to the panel. The finished product is below:

Step 2: finished cut 1 Step 2: finished cut 2 Step 2: finished cut 3

Step 3: Wiring up our data. The key of course is the data, which gives us our RPM's, which you have to get from the ECU/ECM. Our ECU/ECM was located on the passenger side behind the glovebox. The instructions said look for a black wire...expect as anyone who works on electrical can tell you, usually the black wire has either a strip or dot on it. In our case of the 1998 Tocoma, the wire is black with a yellow strip, located on the 26-pin plug on the far left of the ECU/ECM. The picture below has the wire circled in yellow for easy viewing:

Step 3: The magic data wire

We then spliced this wire as so, connecting to our green data wire on the tach (read your instructions to figure out which wire color is correct!):

Step 3: The spliced data wire

Step 4: Power and ground. We attached our ground to a solid piece of the frame, but had trouble finding proper power. Using a mulitmeter, we were able to find out that the optional clock plug (which was connected to our blank panel that we drilled) had the right amount of power. The picture below shows the plug in question. We connected our power to the blue wire with white strip, straight into the clock plug.

Step 4: Power me up!

Step 5: Dimmer switch. The tach came with a wire to connect to the dimmer wire which connected into the dimmer switch. Now, we did this, but it doesn't seem to work (we tried both wires). It seems the tach light draws too much power, and causes the other instrument lights to not work. Very odd. Needless to say, it was getting late so we just wired it to the headlight switch until we can find a better dimmer switch. Sorry, but we don't have a picture of that wiring job (we don't want to encourge people doing this).

Step 6: Put the dash back together. After testing to make sure that the truck started (it did) and that the tach worked (it did), we put the dash back together, and have our finished product:

Step 6: All done

Step 7: Take a corner too fast and attempt to take picture with not enough light. We took the truck for a quick spin, and everything was rockin'!

Step 7: Rock on!