System Check - Digital Cluster

NOTE: Verify the complaint by performing the system check. Use the symptom check to help decide whether the cluster must be returned for repair or if there is a condition in the vehicle circuit. If the symptom in the vehicle is not in the symptom chart, test all of the terminal in the C221 and C222 connectors behind the instrument cluster.


SYSTEM CHECK

1. Turn the IGNITION SWITCH to RUN.
a. The digital SPEEDOMETER segments light one at a time in a rotating pattern to read "188" and then go off one at a time to a blank display.
b. The FUEL bars light up, left to right and then go off right to left. The display then shows the fuel level in the tank.
c. The GAGE bars to the right of the speedometer show the tachometer, "X100", up to the maximum and then goes off.
d. The GAGE display then goes to the last setting, either TACHOMETER, VOLT, OIL, or TEMPERATURE, giving the present vehicle reading.
e. The ODOMETERS display "188888" and "1888.8" and then go to present readings. The mechanical ODOMETER at the lower left also show the vehicle milage (in early production cars only).
f. The red FASTEN BELTS indicator in the electronic cluster comes on (with alarm chime) for approximately six seconds.
g. The UNLEADED FUEL ONLY displays are lit.
h. The OIL/VOLTS and SERVICE ENGINE SOON indicators come on. The TEMP and BRAKE indicators come on in the BULB TEST (crank) position of the ignition switch.

2. Press the FUEL GAGE push-button.
a. The FUEL display changes to an expanded scale showing 1/4 of a tank. If the full level is above 1/4 tank, the display returns to the full tank display when the push-button is released. If the fuel level is below 1/4, the expanded scale remains displayed.

3. Press the METRIC push-button. Observe and press again.
a. The SPEEDOMETER and ODOMETERS change from mph to km/hr and from km to miles and back again.

4. Press the TRIP SET push-button.
a. The TRIP ODOMETER resets to zero.

5. Press the GAGE push-button repeatedly.
a. The display changes from TACHOMETER to VOLTS to OIL PRESSURE to COOLANT TEMPERATURE.

6. Press the GAGE push-button until the TACHOMETER gauge is displayed. Start the engine.
a. The bar graph shows the engine speed.
b. Red line for the V6 is 5500 rpm and 5000 for the 4 cylinder.

7. Turn the park lights on, slide the dimmer control.
a. The LIGHTS ON indicator in the digital cluster comes on.
b. The brightness of the digital cluster decreases when the lights come on if the dimmer control is not set at the maximum brightness.
c. The display brightness is adjustable with the dimmer control.

8. Turn on the headlights to high beams.
a. The HALOGEN indicator and the high beam indicator in the digital cluster come on.

9. Turn on the right hand and then the left hand signals.
a. The turn indicators in the digital cluster blink on and off with the turn lights.

10. Other functions of the digital cluster that may appear while driving:
a. The maximum indicated speed is 85 mph (140 km/hr.). At greater speeds the display will flash 85 mph (140 km/hr.).
b. A CRUISE indicator in the digital cluster comes on when the cruise control system is engaged.
c. With manual transmission a SHIFT arrow comes on to indicate when to upshift for fuel economy.
d. A LOW FUEL display flashes when only two bars of the fuel gage are illuminated.


CONNECTOR PIN-OUT TESTS

The pinout tables give voltages or resistances you should find at C221 or C222 behind the digital cluster.
a. Measure all voltages to ground with the ignition switch in the RUN position.
b. Measure all resistances to ground with the ignition switch in the OFF position.
c. Check that all terminals in the connectors are properly seated and not pushed back out of the connector.


TROUBLESHOOTING HINTS

1. The I/P clusters for all the 85 Somerset Regals are identical. The can be exchanged between cars for testing. The programing for the electronics is in the vehicle wiring.

2. The entire cluster is replaced as a unit. There are no dealer replaceable parts within the cluster. If there is a condition in the digital cluster, the whole cluster is removed and exchanged.

3. If only one display in a cluster does not operate, the condition is probably in the vehicle circuit supplying that display.

4. If the total odometer displays "Error", any one of the following conditions may be the cause:
a. The NVM (non-volative memory chip) is missing.
b. The NVM chip is not functioning properly, or
c. The total odometer electronic driver circuit is malfuntioning. In this case the complete cluster must be removed and returned to a repair center for service. However, the NVM chip, located in the upper right back corner of the cluster, must be removed and remain with the vehicle before shipment.

5. Indicator bulbs (OIL, TEMP, GENERATOR, BRAKE, and SERVICE ENGINE SOON) are replaceable from the front of the digital cluster, without removing the cluster.