Climate Control Symptom Troubleshooting
Symptom
Diagnostic procedure
Also check for
Blower, heater controls, and A/C do not work
Voice communication does not work
Both fans do not run at low speed with the A/C on (but the A/C compressor runs with the A/C on)
  • Blown fuse No. 18 (20 A) in the under-hood fuse/relay box, and No. 36 (10 A) in the under-dash fuse/relay box
  • Cleanliness and tightness of all terminals
The A/C condenser fan does not run at high speed (but both fans run at low speed and the A/C compressor operates with the A/C on)
  • Blown fuse No. 15 (20 A) and No. 20 (7.5 A) in the under-hood fuse/relay box
  • Cleanliness and tightness of all terminals
Both fans do not run at high speed with the A/C on (but both fans run at low speed and the A/C compressor operates with the A/C on)
A/C pressure sensor troubleshooting: A/C pressure sensor circuit low voltage, L13Z1 engine, R18A2 engine, K20Z4 engine, A/C pressure sensor circuit high voltage, L13Z1 engine, R18A2 engine, K20Z4 engine
ECT troubleshooting: ECT sensor 2 circuit low voltage, L13Z1 engine, R18A2 engine, K20Z4 engine, ECT sensor 2 circuit high voltage, L13Z1 engine, R18A2 engine, K20Z4 engine
The A/C compressor clutch does not engage (but both fans run with the A/C on)
  • Blown fuse No. 7 (7.5 A) in the under-hood fuse/relay box, and No. 36 (10 A) in the under-dash fuse/relay box
  • Cleanliness and tightness of all terminals
A/C system does not come on (both fans and the A/C compressor do not work); heater is OK
A/C pressure sensor troubleshooting: A/C pressure sensor circuit low voltage, L13Z1 engine, R18A2 engine, K20Z4 engine, A/C pressure sensor circuit high voltage, L13Z1 engine, R18A2 engine, K20Z4 engine
Blower fan runs slower than expected in cold weather
ECT troubleshooting: ECT sensor 2 circuit low voltage, L13Z1 engine, R18A2 engine, K20Z4 engine, ECT sensor 2 circuit high voltage, L13Z1 engine, R18A2 engine, K20Z4 engine
NOTE: It is normal for the blower to run slowly until the engine coolant temperature begins to rise. If the blower continues to run slowly for an abnormal length of time, continue to troubleshoot the problem.
Passenger's temperature control switch does not work
Cleanliness and tightness of all terminals
HDS does not communicate with the climate control unit or the vehicle