90-96 Cluster Tester Bench Testing
90-96 Cluster Tester by batee.com
Note: This information applies to all cluster testers v3.2.2 and below. Please refer to your USB manual for 90-96 Cluster Testers v6.x.x and above.
Included in the box
90-96 Instrument Panel Tester w/ 34 pin Wiring Harness Connector Installed- Click Here to buy.
AC Power Supply
Video of the Testing Process
- Free Video of this tester in action - Click Here
- Connect the 34 pin wiring harness connector to the 90-96 instrument panel wiring harness connector.
- Plug the AC power supply into the wall.
- Plug the barrel connector output of the power supply into the rear of the 90-96 instrument panel tester. The cluster tester should light up with the following info on the screen:
- Press the green button marked Menu to display the menu:
- Press the yellow button marked down to select the year of the cluster to test.
- If the year range is correct for your cluster, go to step 7. Otherwise press the green button marked Select to change the year range.
- Press the yellow button marked Down to highlight the RPM of the tach needle.
- If the max RPM of your cluster is 6000, skip to step 9. Otherwise press the green button marked Select to change the tachometer range.
- When the year range and tach range settings are correct, press the red button marked Up twice to move the blue highlight bar to "Start tests".
- Press the green button marked Next to start the testing process. The cluster will again show a list of the settings you have chosen.
- If the settings are correct, click the green button marked Next to start the tests. If the settings are not correct, click the blue Exit button to return to the menu screen and fix the settings. Next highlight the Start Tests text and press the green Select button to start the tests.
- The first test is the LCD test. The LCD should light up with 60MPH, a full tank of gas, and the number 123456.7 in the odometer field.
The LCD panel should be lit to full brightness, and it should display text which is completely black and easy to read. One of the most common failures of the cluster is that the polarizing film on the LCD fadeds in the sunlight. If yours is hard to read or unreadable, batee.com can provide a repair kit!
This is a good time to test the connections of the LCD display and wiring harness connector. Move the wiring between LCD and circuit board with your fingers. The display should stay steady. If not, the LCD connector should be replaced. Next, move the wiring on the back of the wiring harness connector around in a circle. Again, the display should remain constant. If not, resolder the 34 pin wiring harness connector to the PC board.
If the information is incorrect, it might indicate the wrong year setting in the menu, and it might indicate a connectivity problem with the LCD panel, and it might indicate a faulty LCD panel.
13. Click the green Next button to continue to the next screen.
Note: At any point during the testing, you can return to the previous screen by pressing the red button marked Last.
All segments of the LCD should light up. If not, this might indicate connectivity problems with the LCD panel, and it might indicate a defective LCD panel.
14. Press the green Next button to continue on to the tachometer tests.
The 0 RPM Tach test screen appears. At this point, the tach needle should point at 0. If not, it may indicate a problem with the tach calibration IC, and it may indicate that the needle needs to be reset to the 0 point. Press Next to continue to the half scale screen.
15. The tachometer needle should point to approximately half scale (3,000 in the case of a 6K tach, or 4,000 in the case of an 8k tach). If not, this may indicate a defective tach calibration IC. Press the green button marked Next to continue to the full-scale tach screen. If the needles do not appear to read correctly, or do not appear to move smoothly, they may be dragging on the faceplate. Pull them away from the face slightly using a thin flat-blade screwdriver.
16. The tachometer needle should point to approximately full scale (6,000 or 8,000 RPM). If not, this may indicate a defective tach calibration IC. If you are installing a replacement tach calibration IC, you should adjust the potentiometer on the tach IC at this point. Adjust the pot so the needle points to full scale, or slightly past full scale if you want to be extra careful! If the needles do not appear to read correctly, or do not appear to move smoothly, they may be dragging on the faceplate. Pull them away from the face slightly using a thin flat-blade screwdriver.
17. This completes the guided portion of the tests. Press the blue button marked Exit to exit to the main menu.
18. Look at the rear of the panel. Check for any bulbs that are not lit and replace any defective bulbs found with factory-equivalent bulbs only.
19. We are applying approximately 12.0VDC to the voltmeter, so that's what it should read.
20. The Oil Pressure, Oil Temp and Coolant Temp gauges should each read approximately half-scale. If they don't, this may indicate a problem with connectivity to the PC board, or a problem with the needle movement itself. If the needles do not appear to read correctly, or do not appear to move smoothly, they may be dragging on the faceplate. Pull them away from the face slightly using a thin flat-blade screwdriver.
21. Remember the GM warning that shipped stuck to the front of these gauges from the factory: The analog gauges are approximate, not 100% accurate. Look at the readings in the LCD if you want to know the exact pressure or temperature measured.
This completes the testing process. Remember that you can always email firstname.lastname@example.org for assistance interpreting these results, and that parts for these instrument panels are available from batee.com - Click Here
This additional information is provided to assist with troubleshooting cluster problems:
Cluster Schematic - click for larger version
Voltage Measurements at the LCD Connector (meter set to DC Volts):
1-gnd: Pin 1 Data Strobe (see image below)
2-gnd: Pin 2 Data Clock (see image below)
3-gnd: Pin 3 Data (see image below)
4-gnd: Pin 4 MClock (see image below)
5-GND: +5V Pin 5 Logic Power Supply +5V
6-GND: 0V Logic Ground
7-gnd: 0V LCD Blanking is held low by cluster and by our tester product
8-GND: Pin 8 (see image below) - I believe this is high when the panel is receiving data (Data Clock is actively transitioning high and low), and low between data packets.
9-GND: 2.95V Voltage set via voltage divider, will be proportional to the power supply voltage.
10-gnd: 0.7857V Voltage set via voltage divider, will be proportional to the power supply voltage.
LCD Pin 1 - Data Strobe
LCD Pin 2 - Data Clock
LCD Pin 3 - Data
LCD Pin 4 - MClock
LCD Pin 8