*NOTE* this is only guaranteed for a 1997 model year.
Connect a jumper between DLC terminals 3 and 4. Then turn the ignition switch to the "run" position. This places the controller in a "blink codes" mode and will cause any error codes stored in the controller to be displayed by the switch LEDs. You will see blink-blink,blink three times indicating code 12. This indicates you are in the diagnostics. Any other code(*) displayed will also blink three times followed by the 12 again. Any other codes will be the problem.
23 Left Front Actuator Position Error
24 Right Front Actuator Position Error
25 Left Rear Actuator Position Error
26 Right Rear Actuator Position Error
31 Lift/Dive Signal Error
32 Lateral Accelerator Switch Error
33 Driver Select Switch Input Error
34 Vehicle Speed Signal Error
To clear error codes, connect one end of a jumper to pin 4 of the DLC connector. With the opposite end of the jumper, alternately plug into and remove from pin 3. Do this three times. Hold each connection for 1 second, and pause one second between connections.
If this works for you and you get codes, post them here and I'll help with the diagnostics. If you wish, give me your e-mail too and I'll scan the diagnostic sheet for the code(*) you have and send them to you.