Rick's Free Auto Repair Advice » BMW

BMW Blower Motor Doesn’t Work

Rick — Mon, 06 Dec 2010 23:46:08 +0000

If you own a 2000-’03 BMW 525I you may have already experienced in inoperative blower motor. If yours has been running fine, consider yourself lucky and start saving money—it’s gonna fail. The motor itself is controlled by a component called the “final stage unit.” It’s located under the dash on the passenger side of the vehicle. The climate control head sends a variable voltage down to the final stage unit, telling the speed to run at. So start your diagnostics by checking voltage on the blue/red wire. Vary the fan speed on the controller head and look for changed voltage on that wire. If it doesn’t change, the control head is bad (you can get those rebuilt).
Next, check for battery power at the red/blue wire and ground at the brown wire. If that checks out, disconnect the connector from the final stage unit and jumper power and ground to the red/green and black/green. If the blower doesn’t kick in, swap the hot and ground and try again. If it still doesn’t run, the blower motor itself is bad. If the motor runs, the final stage unit is bad.

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Erratic heat and cooling – BMW

Rick — Fri, 18 Sep 2009 02:32:02 +0000

BMW climate control units relay on input from two temperature sensors. The most common failure (aside from failure of the entire control unit which is quite high) is the ambient (outdoor) temperature sensor. The sensor is located in an air duct under the front bumper. BMW puts it there to isolate it from hot air coming off the radiator or A/C condenser. However, that under-bumper area is always hitting curbs. Plastic pieces often break off from this area, and when they do, they rip out your ambient temp sensor with. So check that area for damage.

Next, check the interior temperature sensor. It’s located right in the control unit and often gets clogged with dust and dirt. There’s a small fan inside the unit that draws in interior air. The dust and dirt insulate the sensor and it provides incorrect readings. Try removing the faceplate and vacuuming out the dust. If you spray it with canned air, you’ll just lodge more of the dust inside the unit.

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Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I’ve written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you’ve had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Climate Control No Display – BMW

Rick — Fri, 18 Sep 2009 02:16:08 +0000

Climate Control No Display – BMW

This is a very common problem on BMWs, especially the 3-series. Start your diagnostics by smacking the instrument panel–hard. If the display lights up, that’ll prove that it’s getting power. But really, start psyching yourself up for a rebuilt control unit, because that is where this story will end. You will have to remove the unit and send it in to be rebuilt. Costs range from $50-$200. A new control unit from BMW is over $400.

Here are other common problems with the BMW control unit:
Is it switching itself off and on?
The unit resets itself
The control appears to be off but your heater or A/C still runs.
The control unit display is dim.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I’ve written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you’ve had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use