TROUBLESHOOTING (Cont'd) Symptom | Possible causes | Checks and corrections | Page No blower control | Defective water temperature relay | Check for open | AC-9 | Defective heat mode switch | Check for short | AC-9 | Defective water temperature switch | Check for short | AC-20 | Defective Hi-speed relay | Check for short | AC-9 | Defective wiring connection | Check and repair | AC-9 | Defective vacuum circuit | Check for leak and repair | AC-16 Interior temperature does not lower | Blown fuse or circuit breaker | Replace | AC-9 | Defective magnetic clutch | Check and repair | AC-23 | Defective compressor | Check and repair | AC-23 | Defective pressure switch | Replace | AC-9 | Defective expansion valve | Replace | AC-4 | Defective EPR | Replace | AC-4 | Insufficient refrigerant in system | Check and charge refrigeration system | AC-11 | Defective A/C switch | Check for short or open | AC-9 | Defective temperature sensors (in-car sensor, ambient sensor) | Check for short | AC-19 | Defective rheostat | Check for short | AC-9 | Defective power servo unit | Check operation | AC-17 | Defective DVV | Check operation | AC-20 | Defective amplifier | Check operation | | Defective condenser motor | Check operation | AC-21 | Defective A/C relay | Check operation | AC-9 | Defective wiring connection | Check and repair | AC-9 | Defective vacuum circuit | Check for leak and repair | AC-16 Interior temperature does not rise | Defective water valve | Check operation | | Defective temperature sensors (in-car sensor, ambient sensor) | Check for open | AC-19 | Defective rheostat | Check for open | AC-9 | Defective power servo unit | Check operation | AC-17 | Defective DVV | Check operation | AC-20 | Defective amplifier | Check operation | | Defective wiring connection | Check and repair | AC-9 | Defective vacuum circuit | Check for leak and repair | AC-16 Unstable operation (hunting) | Defective vacuum circuit | Check for leak and repair | AC-16 | Poor connection of rheostat | Check and repair | AC-9 | Defective power servo unit | Check operation | AC-17 | Defective DVV | Check operation | AC-20 | Defective amplifier | Check operation | | Poor connection in wire | Check and repair | AC-9 Improper shifting of dampers | Misadjusted control lever or rod | Check and repair | AC-9 | Disconnected control wire | Check and repair | AC-19 | Defective dampers | Check and repair |