Update: You can now purchase a bench test power cable with or without factory connectors Click here
Note: If you purchased the original bench cable without factory connectors installed, Click here for documentation.
Wiring Diagrams and Cluster Pinout - Click Here
Note: The wires which come preinstalled in the black connector housings are clipped into place, and probably don't need to be moved. There are several other wires which have individual plastic sheaths attached. The connectors on these wires have been modified so that they won't catch when inserted into the connector. Their purpose is making temporary connections needed for testing. It may be necessary to temporarily remove the blue or grey plastic wiring combs in order to insert or remove the temporary wires.
Warning: Before connecting power to the wiring harness, make sure that the plastic sheath for each of the unused test wires completely covers the connectors. Also make sure the unused wires/connectors are not resting on the cluster circuit boards.
Plug the two wiring harness connectors into the cluster.
Connect the bench test cable to a source of power.
The four illumination bulbs under the silver caps should illuminate brightly, and all segments all three LCDs should turn on for a few seconds. Note that a few segments are not meant to light up, such as those in the upper left of the leftmost seven segment displays in the speedometer and center panel.
After a few seconds, the lamps should remain brightly illuminated, and all segments should go out except: The MPH and Tach should show "0".
Covering the photocell (to simulate dark operating conditions) should cause the cluster to dim, and shining a light on the photocell (or allowing room light to reach it) should cause it to go to full brightness.
Covering and uncovering the photocell should cause the cluster brightness to change, whether the headlights are on or off.
Insert a red wire into cavity C2. The left turn indicator should illuminate.
Remove the red wire from C2 and insert it into C3. The High Beam indicator should illuminate. Remove the red wire from C3 and insert it into C4. The right turn indicator should illuminate. Remove the red wire from cavity C4.
Connect a black wire pin A9 to show Oil Pressure on the center panel. Connect a black lead to pin C1. The oil pressure should change from from low to high.
Remove the black leads from pin C1 and A9.
Connect pin A10 to ground to show Oil Temp on the center panel. Connect a black lead to pin D6. The oil temperature should vary from low to high.
Remove the black wire from pins D6 and A10.
Connect a black wire to pin A8 to show battery voltage on the center panel. The voltage should read the same as the battery measures, or should be +12V if you're using our bench test cable. Remove the black wire from pin A8.
Connect a black wire to pin A10 to show Coolant temp on center panel. Connect a black lead to Pin D4. The coolant temp should change from 'LO' to high. Remove the black wire from pins D4 and A10.
Connect pin A4 to ground briefly to reset the trip odometer.
Connect a black lead to pin C8. The fuel level graph should slowly change from full to empty. Remove the black lead from pin C8.
To test the tachometer, you'll need a signal generator (or a simple 555 timer circuit). Set it to square wave or sine wave, 1Vpk (2Vpk-pk) amplitude, and 30Hz. Connect the (+) output of the signal generator to C5, and the (-) terminal to the terminal of one of the black wires. This should cause the tachometer to show 500RPM. Increase frequency to 400Hz, when the cluster should show 6000RPM. Don't increase beyond 400Hz.
Testing the speedometer: Warning: Disconnect the odometer. You'll need a signal generator (or a simple 555 timer circuit). Set it to square wave or sine wave, 1Vpeak (2Vpk-pk) amplitude, and 20Hz. Connect the (-) terminal of the sig gen to the C15 terminal of the cluster, and the (+) terminal to the D11 terminal of the cluster. The speedometer should show 18MPH. Increase the frequency to 200Hz, when the speedometer should show approximately 178MPH. Don't increase the frequency beyond 200Hz. Reconnect the odometer.