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I have a 2002 325i that is not heating unless you at 2500rpm or higher also the Aux pusher…

I have a 2002 325i...
I have a 2002 325i that is not heating unless you at 2500rpm or higher also the Aux pusher fan is not working. I have replace the water pump ,therostat, raidator. I have flushed out the heater core. I have check the heater valve its open and close properly. I have purge the air from the system several times. On the aux fan there is 12 volts at the connector It does not move when you turn the switch on or does not run when you turn the AC button on. You can put 12 volts direct to the fan and it will run I have check all the fuses and the are ok.
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Answered in 1 hour by:
12/19/2012
BMW Mechanic: iauto8, ASE Certified Technician replied 9 years ago
iauto8
iauto8, ASE Certified Technician
Category: BMW
Satisfied Customers: 137
Experience: 15 year ASE Auto Technician. European import specialist.
Verified

iauto8 :

Here are the test procedures for no heat. From what you have described it sounds like the coolant supply pipe is blocked. (the one that runs under the intake). I have been able to clear one out by removing the thermostat and blowing compressed air through that pipe. Chris.....

iauto8 :

 










1. Check the water valve, located by the driver's-side shock tower in the engine compartment. With the electrical connector disconnected from the water valve, it should be fully open.

2. If there is no flow through the heater core when the electrical connector is disconnected, check the valve for blockage.

3. At the heater core lines at the firewall, one hose comes from the heater valve and the other is a return line to the reservoir. At the heater valve a hose coming from the back of the head/under the intake manifold supplies hot water to the heater valve. If the engine has overheated, there could be a blockage going to the heater valve. The coolant is actually pumped from the front of the head through a pipe which runs under the intake manifold to a hose connection and then into the water valve. This pipe can collapse and/or plug restricting flow to the water valve.


iauto8 :

Here are test procedures for the Aux fan. Chris.....

iauto8 :

 










1. Condenser fan is controlled by the engine control module and will operate at variable speed depending on coolant temperature, vehicle speed and air conditioning load.

2. As refrigerant pressure and/or engine coolant temperature increases, condenser fan speed will increase accordingly. A pulse width modulated signal is sent from the engine control module to the condenser fan. An integrated output stage unit on the condenser fan will determine the requested speed from the engine control module and activate the fan.

3. Verify that radiator outlet temperature sensor in the lower radiator hose is connected and will provide a resistance which changes with temperature.

4. Inspect pressure sensor located at or near receiver/dryer assembly. Verify proper wire configuration at connector.

5. Small wire, Yellow/Red, going to fan should be a square wave signal which originates at the engine control module. Larger gauge, Black, should have system voltage and Brown wire should have constant ground. If no signal is present from the engine control module when fan should be running, inspect for wire damage between engine control module and cooling fan.


iauto8
iauto8, ASE Certified Technician
Category: BMW
Satisfied Customers: 137
Experience: 15 year ASE Auto Technician. European import specialist.
Verified
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