TM10-3930-660-20 Table 2-2. Electrical Troubleshooting (Cont’d) MALFUNCTION TEST OR INSPECTION CORRECTIVE  ACTION Step 3. Check for defective engine run relay. Test engine run relay and, if necessary, replace the relay, para. 8-24. 15. FRONT WIPER, REAR WIPER, OR WASHER DO NOT WORK Step 1. Check for defective wiper or washer switch. Check switch(es) for continuity. Replace switch(es) if defective, para.  8-8. Step 2. Check for faulty wiring in the circuit. Check for poor ground connections. Refer to electrical schematic, page  F/O-l. Check for broken wires and loose connections, para. 8-46. Step 3. Check for defective wiper or washer motor(s). Replace wiper motor or washer reservoir assembly if motor(s) are defective, para. 17-3, 17-4, and 17-5. 16. HEATER  FANS AND CAB FANS DO NOT WORK Check if circuit breaker (CB8) is tripped. l The circuit breakers will trip if there is a shorted or grounded wire. l The  circuit  breakers  will  automatically  reset  after  cooling.  They cannot be reset manually. l Under  normal  operating  conditions,  circuit  breakers  should  never require replacement. However, if a circuit breaker does not reset after it has cooled, the circuit breaker is defective and must be replaced, para. 8-12. Check circuit for shorts, broken wire or bad ground. Refer to electrical schematic, page F/O-l. 17. ONLY ONE HEATER FAN WORKS ON HIGH SPEED Check for bad ground connection, loose connections, or defective switch. Check switch and wires for continuity. Refer to page F/O-l and paragraph 8-46. Replace switch if required, para.   8-8. If necessary, replace broken wire, para. 8-46. 2-20