I happened to acquire one of these recently and had to go digging for the instructions. Given the website has been dead for 15 years, I am reproducing the instructions here for others to benefit. Good luck with your Merkur!
MerkMetertmInstallation Instructions: XR4Ti
Installation is very simple and should easily take less
than one hour. Installation of the MerkMeter basically involves removing
the instrument cluster, inserting the meter into the preexisting slot, running
a wire (provided) to the computer, and connecting this wire to the oxygen
sensor signal wire at the computer wiring harness. Most of the time
required will be spent in removing and replacing the instrument
read through these instructions completely once before proceeding. Although they may appear lengthy, we have just
tried to be thorough and not assume any previous experience on the part of the
installer. If more detailed information is required,
please contact us via email for help.
CAUTION: Although the MerkMeter has not been shown in
practice to be sensitive to damage caused by static discharge, it does have a
semiconductor component. As such, care should be taken to handle the
MerkMeter outside its protective anti-static bag as little as
possible. Under no circumstances should it be handled while an
electrical source is connected.
Philips head screwdrivers
7mm nut driver or socket
19 mm open-end wrench (For late model cars with cruise
Step One: Remove Instrument Cluster
Note: The step order outlined here may be slightly different than that
described elsewhere, but is the easiest procedure we have found in removing
many XR4Ti instrument clusters. TIP: Before
removing the instrument cluster check for any malfunctioning light
bulbs. Now would be a good time to replace them.
Remove screw from upper steering column shroud and
three screws from the bottom of the lower steering column shroud and
remove the shroud. Note: One screw is
near the steering wheel and two are at the hood release latch.
four screws retaining instrument cluster bezel. Carefully pull
bezel free and remove the panel illumination control and intermittent
wiper control rheostats. TIP: Carefully push
these controls out the front of the bezel and disconnect them from their
wiring harness by gently pulling on the connector.
four screws holding instrument cluster to dash and pull cluster towards
the steering wheel. Do this gently and only far enough to
allow your hand to reach behind the left side of the cluster.
the turbo boost gauge vacuum line by pulling it free of the nipple on the
back of the instrument cluster. TIP: If this
hose is old, it may be necessary to twist it a bit to pull it
free. The OE hose frequently develops a leak near the
connection with the nipple, so now would be a good time to replace this
hose if it is old.
the cluster wire harness by gently pulling on the connector.
the speedometer cable connector where it is attached to the back of the
instrument cluster. While pressing on the “button” on the side
of the white plastic cable latch, gently pull the cable free of the
cluster. The cable should come free easily without much
required force. TIP: In later model cars
equipped with cruise control there is little or no slack in the two-piece
speedometer cable. It will be necessary to disconnect the
cable inside the firewall (near the fuse box) using a 19mm
wrench. Only pull the cluster far enough to disconnect the
cable as described above.
cluster from dash.
Step Two: Configure MerkMeter
Dot / Bar Mode
MerkMeter can be configured to display in either Dot Mode (one light at a time displayed) or Bar Mode (current reading and all lights
below are on). The MerkMeter is shipped with Dot Mode as the default and is the
To set the MerkMeter to operate in Bar Mode, install the shorting jumper on J1 (See Figure 1)across BOTH pins.
Instantaneous / Dampened Mode
quickly the MerkMeter display responds to changes in the output of
the oxygen sensor can also be set. In Instantaneous Mode the MerkMeter will display
the voltage changes in the oxygen sensor immediately. While
in Dampened Mode,
the MerkMeter will not be as quick to change in response to changes
in the oxygen sensor output. The MerkMeter is shipped with Instantaneous Mode as the default and is
the recommended mode.
To set the MerkMeter to operate in Dampened Mode, install the shorting jumper on J2 (See Figure 1)across BOTH pins.
Step Three: Install MerkMeter in Instrument
Remove panel insert from the back of the instrument
cluster. Simply squeeze the tab to unlock and slide out the
insert blank. (See Figure 2)
Remove the protective
paper from the two self-adhesive pads on the MerkMeter.
Carefully slide the
MerkMeter into the slot in the back of the instrument cluster with the
adhesive pads facing up. (The side with the
electronic components will be on the bottom.) When
properly installed, the three red LEDs will be on the left when viewed
from the front. Be careful not to allow the adhesive pads to
stick to the cluster yet.
Continue to slide the MerkMeter into the slot until the
display socket of the MerkMeter is securely pressed into the opening and
is flush with the front of the panel.
Carefully and firmly
press upward on the back of the MerkMeter to allow the adhesive pads to
stick to the two small plastic tabs at the top of the slot while ensuring
the MerkMeter remains in the proper position. NOTE: The meter
may also be secured using the large white wire tie. The wire
tie should be routed through the hole on the MerkMeter and the eyelet on
the tie then secured to the hole just above the mounting slot with a
suitable screw (not included). It is easiest to place the tie
through the MerkMeter hole first and only tighten it
slightly. Then the screw should be inserted through the eyelet
and threaded into the hole a couple turns. If you keep as much
slack as possible in the tie, you can rotate the MerkMeter and insert it
into the mounting slot. When the meter is in position, the tie
can be slowly cinched down as the slack is carefully worked out of the
tie. The screw should then be threaded the rest of the way into the hole. Do not over-tighten the tie or the screw.
Remove the nuts from
the electrical supply studs on the back of the cluster indicated in Fig
“Power” and “Ground” using a 7 millimeter nut driver.
Attach the RED wire to the
stud indicated in Fig 2 as “Power” and secure it with
one of the nuts.
Place the BLACK wire on the
stud indicated in Fig2 as “Ground”. Also
place the tab adaptor used to secure the BLACK ground extension wire onto
the same stud. Attach wire and tab with the remaining nut.
Attach the spade
connector on the BLACK ground extension wire to the
chassis grounding screw on the dash support bracket directly behind the
instrument cluster. Loosen the screw a few turns, slide the spade
connector under the screw and retighten the screw. NOTE: This extra
ground wire is needed since the instrument cluster ground Ford provided
via the stock wiring harness is inadequate.
Check again that all
wire connections are correct. Ensure that the ring connectors are not in
contact with any other nearby studs. Be sure the chassis
ground screw is tight and all wires are secure.
sound-deadening panel from beneath the glove box.
The male connector
end of the oxygen sensor signal wire should be carefully routed from the
cluster, through the dash opening, and down and under the center console
to the passenger side foot well area. (It may also be possible
to route the wire down and through directly behind the
radio.) A length of coat hanger wire may assist in fishing the
the female connector on the extension signal wire to the GREEN wire
on the MerkMeter. Attach the grounding wire to the tab adaptor
installed on the cluster ground stud. The instrument cluster
should be temporarily placed in its mounting hole or on the dash.
Step Four: Connect Oxygen Sensor Signal Wire
Note 1: The
EEC-IV computer receives the input from the oxygen sensor via Pin 29 on
the computer wiring harness. The oxygen sensor signal wire should be DARK GREEN with a dashed PURPLE stripe but might
vary. Verify the proper wire by tracing it to Pin 29 on
the connector. DO NOT RELY ON
THE WIRE COLOR ONLY. Connecting
the MerkMeter to the incorrect wire will cause it to malfunction. A wrong connection may damage the MerkMeter, the computer,
and/or some other part of the vehicle.
Note 2: The splice connector supplied
with the MerkMeter is an Insulation Displacement Connector
(IDC). This means the connector will pierce the wire’s insulation
to make an electrical connection. If the connector is subsequently
removed, the wire’s conductive core may be exposed and subject to short
circuits and corrosion if it is not properly
reinsulated. Alternative splicing techniques exist and the
installer is free to use the technique of their choice. In addition,
the installer may choose to tap into the oxygen sensor signal wire at any
point of their choosing. The wire is easily accessible near the
actual sensor itself, but his will necessitate running a signal wire through
the firewall. The signal wire provided with the MerkMeter will
probably not be long enough to accomplish this alternate connection.
the sound-deadening panel from beneath the glove box. This is
attached with some clips to the bottom of the glove box and two bendable tabs
on the firewall.
Carefully pull the computer down and free of its
retaining bracket under the glove box.
Locate the oxygen
sensor wire at Pin 29 on the wiring harness connector by
using Figure 3a and Figure 3b for reference. It may
be necessary to pull back some of the wire bundle insulation for a better
view of the connector and wires. Note:
If you find it necessary to disconnect the computer from the wiring
harness, DISCONNECT THE NEGATIVE
BATTERY CABLE under the hood first. Use
caution in doing this. Sparks near an automotive battery can ignite explosive gases generated by the battery with
potentially catastrophic results to you and/or your car.
After verifying that you have found the correct wire
for the oxygen sensor signal, splice into that wire. A tap
splice has been provided for this purpose with the proper connector for
the signal wire that feeds the MerkMeter. Figure
4 illustrates how the splice connector should be
oriented on the wire. Carefully close the two halves of the
connector shell andSLOWLYsqueeze
them together with the pliers until the connector locks
CAUTION:Care should be taken that the wire is
properly placed before the connector is squeezed closed. It is
possible (though unlikely) that misalignment could result in a broken oxygen
MerkMeter extension signal wire securely into the socket on the tap
Step Five: Test the Installation
Reconnect the turbo boost gauge vacuum line, harness
connector, and the speedometer cable to the instrument
cluster. TIP: You
should feel a distinct click when the speedometer cable is properly
If it was necessary
to disconnect the computer from the wiring harness, reconnect it
now. Also reconnect the battery negative
cable. Note the above cautions in working around the battery.
Turn the ignition key
to the “II” (Run) position. All warning lamps on the
instrument cluster should light. If the MerkMeter is
properly connected, the leftmost LED (“Lean”) should
illuminate. If the rightmost LED (“Rich”) lights (or all LEDs
if the MerkMeter is configured in Bar Mode) , then check that
the signal wiring is properly connected from the meter to the
computer. If no LEDs light, check that the power and ground
wires are properly connected and the wiring harness is properly seated in
Once the MerkMeter
passes the test above, start the car and run it two minutes above 2000
rpm. If the car is cold, you should see the lights on the
MerkMeter gradually light from left to right. If the car is
warmed to normal operating temperature, you will soon see the lights in
the display start to illuminate in an oscillating pattern from left to
right and back again. If the display changes in either of
these ways, it is properly installed.
Step Six: Reinstall all Components
the MerkMeter has been successfully tested, all removed components may be
reinstalled. As many shop manuals point out so helpfully:
"Installation is the reverse of removal".
Reinstall the computer in its bracket.
Use the provided wire
ties where needed to secure the extension oxygen sensor signal wire under
sound-deadening panel under the glove box.
instrument cluster into the dash securing with the four
screws. TIP: As you push the cluster back into the dash, be
careful the speedometer cable does not kink. It may be
necessary to pull the cable gently back through the firewall from the
engine compartment. NOTE: If it was necessary to disconnect
the speedometer cable at the firewall, reinsert the cable end and
reconnect the attaching nut at this time.
reconnect wiper and light dimmer rheostats in the cluster
Reinstall cluster bezel using the original four screws.
steering column shroud with three screws.
Reinstall the top
steering column shroud with one screw.