Climate control not working (under any circumstances)
- Make
- Alfa Romeo
- Model
- 159 Factory Service Manual
- Year
- 2005–2011
- Section
- Climate control › Climate control not working (under any circumstances)
CLIMATE CONTROL NOT WORKING (UNDER ANY CIRCUMSTANCES)
When the on/off switch is pressed, the climate control does not work
| 0 | PRELIMINARY CHECKS | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
|---|---|---|---|---|
Check:
See Test 5040OB Air conditioning system operational check (pressure)
| Move on to Step 1 | 1.Fuses blown | 1.Change the blown fuses | |
| 2.Relay damaaged | 2.Replace the relay | |||
| 3.Gas pressure not correct | 3.Search for and eliminate leaks and top up climate control system to correct level | |||
| 4.Incorrect operation of engine cooling fan. | 4.Carry out the test. | |||
| 1 | CHECK ON OPERATION OF COMPRESSOR BY CLIMATE CONTROL SYSTEM CONTROL UNIT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Check the following conditions: ambient temperature at least 5°C and outside temperature sensor reading > 5°C. With the engine started and the compressor on (check that the snowflake symbol lights up), set the control unit to the AUTO position, the temperature to maximum cold LO and the distribution to the front position. Check, using the Examiner, that the instrument does not show any short circuits for the compressor circuit. In these conditions, check that the compressor comes on by opening the bonnet and taking a look. | End of diagnosis | 1.The snow flake symbol in the display does not light up (but the compressor is on). | 1.Move on to Step 3 | |
| 2.The LED with the snowflake symbol comes on (but the compressor does not switch on). | 2.Move on to Step 2 | |||
| 3.The outside temperature reading is incorrect. | 3.Move on to Step 3 | |||
| 4.Compressor short circuit. | 4.Move on to Step 3 | |||
| 5.Errors on CAN line | 5.Move on to Step 3 | |||
| 2 | CHECKS USING DIAGNOSTIC EQUIPMENT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Keeping the diagnostic equipment connected check that there are no errors:
| Move on to Step 3 | 1.Climate control node not working. | 1.Move on to Step 4 | |
| 2.CAN line error. | 2. Continue as instructed by the diagnostic equipment | |||
| 3.The engine management control unit does not give the go ahead. | 3. Continue as instructed by the diagnostic equipment | |||
| 3 | CHECKS USING DIAGNOSTIC EQUIPMENT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Keeping the Examiner diagnostic equipment connected, check the following at the engine management control unit:
| Move on to Step 5 | 1.Relay not working | 1. Replace the compressor operating relay | |
| 2.Error at the linear sensor | 2. Carry out the Op. 5040BC CHECK ON ENGAGEMENT/DISENGAGEMENT OF COMPRESSOR THROUGH LINEAR SENSOR | |||
| 3. Error (short circuit or open circuit) at the evaporator temperature sensor. | 3. Restore the correct wiring for the evaporator temperature sensor. | |||
| 4. Error in the evaporator temperature sensor. | 4.Replace the evaporator temperature sensor Op. 5040B64 SENSOR ON EVAPORATOR FOR A/C ECU - R + R | |||
| 5. Error (short circuit or open circuit) at the outside temperature sensor. | 5. Restore the correct wiring for the outside temperature sensor. | |||
| 6. Error at the outside temperature sensor. | 6. Replace the outside temperature sensor Op. 5010D12 | |||
| 7. Error at the fan. | 7. Move on to Step 5 | |||
| 8. Compressor wiring broken. | 8. Restore the correct wiring. | |||
| 4 | CHECK ON CLIMATE CONTROL NODE ELECTRICAL CONNECTIONS | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
| With the engine switched off, remove the control from the dashboard support and disconnect the cables connector from the control unit visually inspecting for any damage at the connector contacts and reconnect it correctly for check for any false contacts. | Move on to Step 5 | 1.Electrical connections loose or damaged. | 1.Restore the loose or damaged electrical connections | |
| 2. The electrical connections are not loose and the LED with the snowflake symbol does not light up. | 2.Replace the climate control system control unit Op. 5040D15 CONTROL UNIT WITH AUTOMATIC DUAL ZONE AIR CONDITIONER KNOBS AND BUTTONS - R.R. | |||
| 5 | CHECK ON CORRECT OPERATION OF FAN BY CLIMATE CONTROL SYSTEM CONTROL UNIT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
With the engine started, set the climate control system control unit to the AUTO position, adjust the temperature to 22 °C, place the recirculation at the outside air intake and the distribution to the front position. Adjust the fan button (+ side) gradually increasing the speed set and then decrease the speed using the button (- side), thereby checking the effect of the air flow rate variation. | End of diagnosis | There is no variation in the air flow rate. | Move on to Step 6 | |
| 6 | CHECK ON ELECTRICAL CONNECTIONS AND FAN OPERATION | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Check whether the electrical wiring connections are loose. Disconnect/reconnect the connection to the engine mounting. Disconnect the connector and connect to a feeder. In these conditions the motor should rotate at the maximum speed indicating that the operating module is not working | End of diagnosis | 1.Electrical connections loose | 1.Renew the correct connections | |
| 2.The fan does not work. | 2.Replace the fan | |||
| 3.The operating module does not work. | 3.Replace the fan operating module Op. 5040C40 AIR CONDITIONING FAN MOTOR SWITCH - R.R. |
When the on/off switch is pressed, the climate control does not work.
| 0 | PRELIMINARY CHECKS | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
|---|---|---|---|---|
Check:
See Test 5040OB Air conditioning system operational check (pressure)
| Move on to Step 1 | 1.Fuses blown | 1.Change the blown fuses | |
| 2.Relay damaaged | 2.Replace the relay | |||
| 3.Gas pressure not correct | 3.Search for and eliminate leaks and top up climate control system to correct level | |||
| 4.Incorrect operation of engine cooling fan. | 4.Carry out the test. | |||
| 1 | CHECK ON COMPRESSOR OPERATION BY MANUAL CONTROL | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
| Check the following conditions: with the ambient temperature at least engine 5 °C. With the engine started and the compressor on (check that the snowflake symbol lights up), set the temperature to maximum cold and the distribution to the front position. Also check that there are no short circuits to earth for the compressor circuit by connecting the diagnostic equipment. In these conditions, check that the compressor comes on by opening the bonnet and taking a look. | End of diagnosis | 1. The snowflake symbol in the display does not light up (but the compressor is on). | 1.Move on to Step 4 | |
| 2. The LED with the snowflake symbol comes on (but the compressor does not switch on). | 2.Move on to Step 2 | |||
| 3. Compressor short circuit. | 3.Move on to Step 3 | |||
| 2 | CHECKS USING DIAGNOSTIC EQUIPMENT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
| Connect the Examiner diagnostic equipment and check that there are no errors at the Engine Management Control Unit | Move on to Step 3 | The engine management control unit does not give the go ahead. | Continue as described by the diagnostic equipment | |
| 3 | CHECK USING DIAGNOSTIC EQUIPMENT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Keeping the diagnostic equipment connected, check:
| Move on to Step 5 | 1.Relay not working | 1.Replace relay T5 (it is the middle one in the right row) | |
| 2.Error at the linear sensor | 2.Carry out the test See Test 5040BC Climate control compressor linear sensor on/off check | |||
| 4 | CHECK ON CLIMATE CONTROL SYSTEM CONTROL UNIT ELECTRICAL CONNECTIONS | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
| With the engine switched off, remove the control from the dashboard support and disconnect the cable connector visually inspecting for any damage at the connector contacts and reconnect it correctly for check for any false contacts. | Move on to Step 5 | Electrical connections loose or damaged. | Renew the electrical connections | |
| 5 | CHECK ON CORRECT OPERATION OF FAN | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Check whether the electrical wiring connections are loose. Disconnect and visually inspect for damage at the connector contacts and reconnect the connection to the motor mounting. Check that it rotates at all speeds by activating it using the switch. If it does not turn at maximum speed, check the fan maximum speed relay. See J041 PASSENGER COMPARTMENT AIR FAN MAXIMUM SPEED RELAY Disconnect the connector for the fan and connect to a feeder. In these conditions the motor should rotate at the maximum speed indicating that the operating module is not working | Move on to Step 6 | 1.Electrical connections loose or damaged | 1. Renew the electrical connections | |
| 2.Fan not working. | 2.Replace the fan | |||
| 3.Fan only turns at the maximum speed supplied directly by the vehicle battery. | 3.Move on to Step 6 | |||
| 6 | CHECK ON CORRECT OPERATION OF MAXIMUM SPEED RELAY | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Check whether the electrical wiring connections are loose, disconnect visually inspecting for any damage at the connector contacts. Reconnect the connection to the resistor. Check the operation of the fan at the maximum speed: if it only works at the maximum speed, the relay is broken. Check whether the resistor is broken by checking the electrical continuity in accordance with the test. See Test 5040CF Sequential procedure for checking air conditioner fan resistor operation | Move on to Step 7 | 1.Electrical connections loose or damaged. | 1. Renew the electrical connections | |
| 2.Relay broken. | 2.Replace the ceramic resistor Op. 5040C48 A/C FAN MOTOR RESISTOR - R+R | |||
| 3.Resistance values faulty | 3.Replace the ceramic resistor Op. 5040C48 A/C FAN MOTOR RESISTOR - R+R | |||
| 7 | CHECK ON CORRECT OPERATION OF SPEED SELECTOR AT THE CLIMATE CONTROL SYSTEM CONTROL UNIT | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
Check whether the electrical wiring connections are loose, disconnect visually inspecting for any damage to the connector contacts. Reconnect the connection to the selector on the climate control system control unit. Check whether the selector at the control unit is broken by measuring the electrical continuity in accordance with the test See Test 5040DF Sequential procedure for checking air conditioner fan operation | Move on to Step 8 | 1.Electrical connections loose or damaged. | 1. Renew the electrical connections | |
| 2.Fan not working. | 2.Replace the speed selector knob Op. 5040D23 KNOB (ONE) FOR ANY OF THE AIR CONDITIONING CONTROLS - R.R. | |||
| 3.Power supply to the relays not correct. | 3.Replace the climate control system control unit Op. 5040D17 CONTROL UNIT WITH MANUAL AIR CONDITIONER KNOBS AND BUTTONS R R | |||
| 8 | CHECK ON CORRECT OPERATION OF FAN MAXIMUM SPEED OPERATING RELAYS | ALL OK | PROBLEMS ENCOUNTERED | ACTION |
| Check whether the electrical wiring connections are loose. Disconnect visually inspecting for any damage to the connector contacts. Reconnect the connection to the relay. Check that the relay is working properly by providing it with a direct 12 V supply. | End of diagnosis | 1.Electrical connections loose or damaged | 1. Renew the electrical connections | |
| 2.Maximum speed operating relay not working. | 2.Replace the maximum speed operating relay Op. 5040C48 |
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