How to install a tachometer in your Ford F150 using the PCM. Article by aty.
*NOTE*: Only attempted on an 2002 F-150 4.2L V6
Things Needed:
- D-Sub Connecter (Female) - you need the pins : $1.98 @ radio Shack
- #30 drill bit
- Tachometer
- Extra wire
- About 30-40min
Wiring a tachometer, first things first put it where you want it. Where ever
you install the tachometer isn’t part of this How-To. That part comes
in the instructions with the tach. Alright let’s get started.
Step 1 - Running the wires
On the floor board of the drivers side toward the firewall, there should be a
grommet about 1 to 1 1/2 in is size. It’s kind of hidden behind some of
the flooring cover. That’s where I ran my wires through the firewall rather
that having them going through the drivers side door to the engine compartment.
If not run them however.
Step 2 - Wiring
Following the directions provided by the manufacturer (wire colors may vary).
Wires provided by the tach. I bought tachometer at O'Riley’s auto parts
for $30, they have two for that same price I wanted the smaller one but they
were out so I got the bigger one, and I gotta say I’m happy with it now.
Okay back to the topic. Open the fuse panel below the driver’s side dash.
The fuse diagram is in your owners manuals [ed: we have some owners manuals
posted here for 2008, 2007, 2006,
if in doubt, ask about your truck in our forums.].
- White - connect to dash lighting v12 fuse
- Red - connect to +v12 fuse (only when key is on, radio, lighter)
- Black - ground it to the firewall.
- Green (tach) - goes to negative side of coil, duh! (Keep reading)
On the back of the tach. That I have has a switch to select between 4 cyl,
6 cyl, 8 cyl. And of course it’s a 6 cyl so go figure. If you own a vehicle
when ford started putting EDIS (Electronic Distributor Ignition System) in the
cars, in other words no distributor is need, just more wires and sensors and
expensive coil packs are needed. Anyways after research and countless hours
reading forums and looking at wiring diagrams =) hope you enjoy.
Step 3 - To the PCM!
The PCM (Power Control Module) is located on the passenger side firewall,
behind the battery. To gain access to the connecter, remove the battery. And
unlighted the fastener that has the connector connected to the PCM. On the connector
it has a cover covering the wires connected to the connector, it’s black.
Remove the cover.
Once you remove the cover you can see the numbers on each side of the connector.
The one you need to locate is pin hole #48, if you already have a wire coming
out of #48 just splice to it. BE SURE YOU DOUBLE-CHECK THE PIN #. Because the
wrong splice can cause havoc on your wiring system and cause things to fail
for unknown reasons. Once you’ve located the right pin hole you need to
drill through, be careful as possible. Use a #30 dill bit. Take a paper clip,
or safely pin and push the FOD (Foreign Object Debree) out of the pin hole,
make sure you get it all because it will be a pain when you put the wire through.
Crimp the female connector on the tach wire. On the other end open it a little
so that the pin doesn’t push the connector and the wire back out. Install
the cover back on the connector and fasten the fastener back down on the PCM
connector and reinstall the battery (ground first).
Tachometer Installation Photos
PIC’s AHHHHH Everyone loves pics!!!!
My Lovely Tach. Only $30 =) NEXT!
Here is the grommet on the floor under the drivers side. And
my blurry hand.
Eeeeee! My dirty engine compartment. The wires are in the top
right hand corner. There green and blue. (The ground was to short so I had to
connect some more wire to it, and so was the green as well.)
The ground and the tach wire. (blue=ground, green=tach).
TO the PCM connecter we go! (There is no pic of the connector
because I'm too lazy to pull out the battery =) I’ll draw you a pic instead)
the tach wire is also blue because I found some old radio wire around and split
This is what the back of the connecter should look like where all the wires
go in to it. Locate pin #48 and drill (straight) threw but only enough so that
you have a hole for your wire. Don’t go all the way threw. Using a paper
clip or something small enough to go in the hole from the front and push the
stuff from drilling out. Take the D-computer pin and your tach wire and crimp
the wire to the pin. Insert the tach wire in the hole you drilled and look at
the front and make sure the connecter pin is open like the others next to it.
Then plug it back in and reinstall everything. (Be careful there are a lot of
wire around).
NOTE: It appears that the process is the same for 2001 4.2L trucks. See additional tachometer install pictures at F150Online.
Keywords: ford f150 2002 02 f-150 tach tachometer gauge guage rpm engine monitor v8 6 8 cylinder wire wiring how to technical article
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2008-04-26 at 6:19pm
To clarify, the white wire can be connected to anything that gets 12 volts when you turn your lights on, i used a wire on the harness for my stereo. i also used my stereo wiring for the red wire, it just needs to maintain 12v when you turn the ignition on. If you still want to wire them to the fuse box you can purchase two "add a circuits" at the auto parts store, they plug right in place of your fuse, your fuse plugs in the top, and there is a wire on it ready to be spliced. Last but definitely not least i tried to take a shortcut that a muscle car guru told me, and rather than pulling the battery and drilling a hole in the connector, i spliced the green wire directly to the green wire on the coil, THIS WILL NOT WORK. With a distributorless ignition system you need a tach adapter box, unless of course you follow this article and connect it to the pcm which will save you around $70 if im not mistaken.