Checking the Blower Fan Control
Checking the blower fan control
Checking the function of the blower fan
- Ignition on
- Activate the blower fan: Turn the blower fan knob.
Check whether the blower fan starts.
1. The blower fan operates normally
2. The blower fan runs but at an incorrect speed (for example, half speed, full speed or constantly)
3. The blower fan does not operate.
Select one of the above alternatives to proceed with fault-tracing.
1 - Troubleshooting complete
2 - Checking the control current
3 - Checking components and wiring
-------------------------------------------------
Checking the control current
- Ignition on.
Check the control current from the climate control module to the power unit: Turn the fan speed knob between the minimum and maximum positions. The signal must vary between approximately 0 and 10 mA from the minimum to maximum positions.
Try a new climate control unit if the control current is faulty.
Remedy as necessary.
Other information:
- To access or replace the climate control module, see Climate control module (CCM), replacing Service and Repair
- To access or replace the power unit, see Blower fan motor / power unit, replacing Blower Fan Motor/Power Unit, Replacing.
Was a fault detected?
Yes - Replace power unit
No - Checking the wiring
-------------------------------------------------
Checking the wiring
Caution! The blower fan motor power unit is very sensitive to short-circuits and excess current. Do not damage the power unit when taking readings. Take readings with the power unit connector disconnected when checking the wiring.
Check the signal cable between power unit terminal #B2 and the blower fan motor positive terminal. Check for a short-circuit to supply voltage.
Check the ground cable between power unit terminal #B1 and the blower fan motor negative terminal. Check for a short-circuit to ground.
Remedy as necessary.
Other information:
- To access the climate control module or connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the blower fan motor or power unit, see Blower fan motor / power unit, replacing Blower Fan Motor/Power Unit, Replacing
- For other values, see Signal specification Signal Specification, Climate Control Module (CCM)
- Checking wiring and terminals Checking Wiring and Terminals.
Was a fault detected?
Yes - Verification
No - Replacing the power unit
-------------------------------------------------
Checking components and wiring
Caution! The blower fan motor power unit is very sensitive to short-circuits and excess current. Do not damage the power unit when taking readings. Take readings with the power unit connector disconnected when checking the wiring.
Check the function of the blower fan motor: Connect its positive terminal to battery voltage and the minus terminal to ground.
Check that fuse 26 in the in the fusebox in the passenger compartment is intact. If the fuse has blown, check the signal cable between fuse number 26 and power unit terminal #A2. Check for a short-circuit to ground.
If the fuse has blown, also check the signal cable between power unit terminal #B2 and the blower fan motor positive terminal. Check for a short-circuit to ground.
Check:
- the control signal cable between climate control module terminal #A3 and power unit terminal #A1
- the diagnostic signal cable between climate control module terminal #A2 and power unit terminal #A3.
check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
Remedy as necessary.
Other information:
- To access the climate control module or connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- To access or replace the blower fan motor or power unit, see Blower fan motor / power unit, replacing Blower Fan Motor/Power Unit, Replacing
- For other values, see Signal specification Signal Specification, Climate Control Module (CCM)
- Checking wiring and terminals Checking Wiring and Terminals.
Continue - Verification
-------------------------------------------------
Replacing the power unit
Replace the power unit according to Blower fan motor / power unit, replacing Blower Fan Motor/Power Unit, Replacing.
Continue - Verification
-------------------------------------------------
Verification
Hint: After the repair it is necessary to check that the fault has been rectified.
- Ignition off.
- Connect the connectors, install the components, etc.
- Ignition on.
- Read the diagnostic trouble codes.
If the status of the diagnostic trouble code has changed to an intermittent fault this indicates that the fault has been rectified.
Has the status of the diagnostic trouble code changed?
Yes - Troubleshooting procedure complete
No - Fault-tracing information
-------------------------------------------------
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - Exit Fault-tracing
No - Attempt New Test
------------------------
Attempt New Test - Checking the function of the blower fan
-------------------------------------------------