To perform guage self-test, locate diagnostic socket behind right headlight. Remove cover from socket A, plug wire in to #7. Turn on ignition, Press button on diag. socket 3 times within 5 seconds. This puts the instrument cluster in to self test mode. The guages should go to predetermined position. Temp, start of red area. Gas,1/2 tank. Speedo, needle in vertical position. Tach, vertical position. If 1 or more guages do not conform to these specs, you have a guage or circuit board problem. If the guages check ok, problem is sensors/wiring/conectors. You might check the cluster for fault codes. Socket 7, key on, press button 1 time. Wait for fault codes to flash out. 1-1-1 indicates = no faults. 1-2-1 = temp sensor cycle too short. 1-2-2 = ect interval too long.