How to Hook Up a Tachometer to a Toyota Pickupby Christian Killian
Installing a tachometer on your Toyota pickup is a fun do-it-yourself project that will add an extra sense of security and control over the engine on your vehicle. The new tachometers that are being sold today are mostly electric and very simple to hook up. Most of these are four-wire tachometers with have back lights, and many can be used on any size engine with a simple flip of a switch. There are many companies selling these tachometers, so shop around and get the one that best suits your needs.
Decide where you would like to mount your tachometer before you start. You want it to be visible, but at the same time, you want to see the dash around it. Remember that there are other gauges there that you will need to see.
Mount the tachometer in the location you choose, and be sure you can get to the wires in the back of the tachometer. There will be four wires that are coming from the back of the unit. The first one is a hot or power lead, the second is a ground, the third is listed as the trigger wire and the fourth is the wire that will attach to the lighting in the car to dim the back light.
Route the power lead, normally a red wire, to a switched power source. A great place to pick up power is in the fuse box. There are often extra connections in there for this purpose.
Strip 1/4 to 5/8 inch of insulation off the end of the hot lead with wire strippers. Attach the appropriate connector to the wire by inserting the stripped wire into the connector and crimping it shut. Do not plug in this wire yet.
Route the trigger wire out through the fire wall of the vehicle. If you are drilling a new hole, be sure to use a grommet on the hole to protect the wire against chafing. You can often slide the wire through an existing grommet and not drill any holes unnecessarily.
Connect a ring connector to the trigger wire after it is through the fire wall, or you might not get it through without making a larger hole. Find the ignition coil under the hood.
Connect the trigger wire to the coil at the negative connection on the coil using a socket and ratchet to loosen the nut on the post. Sometimes you will find that the vehicle has a tachometer connection on the distributor; you can use this if the vehicle has one.
Locate a grounding point for the tachometer. This can be any point on the chassis that is metal; in most cases there will be several already in use under the dash. Often it is bolt or screw.
Attach a ring connector to the black or ground wire from the tachometer and connect it to one of these ground points. Make sure that the ground is clean and solid, or the tachometer will not function.
Locate a power wire connected to any of the dash lights under the dash. Attach this last wire to one of these wires using a crimp-on wire tap.
Clean up the wires by routing them all together from the tachometer until they disappear under the dash to make the job look professional. Wire loom is a great addition to a job such as this to dress up the wires, and you can buy it at any auto parts store.
Start the vehicle and verify that the tachometer is working. If all of your wires are correct, it should be reading somewhere close to your idle speed. If it is reading very high, you have a wire wrong, so go back and check them all.
- The wire colors are not always going to be as outlined here. Some manufacturers use different colors, so always verify which wire is what before making connections.