logo
The Volvo Parts, Accessories &
Performance Specialists Since 1963


Heater Blower Motor Diagnostics

Created on 2011-03-09 by IPD Staff

If your blower fan is inoperative on your 850 or S/V70 up to 2000, start with the basics and check the fuse.

From there proceed to the blower fan itself located behind the glove box. To access it, remove the Torx 25 screws holding the glove box in place and remove the box. Remove the Torx 25 screw holding in the pass side knee bolster cover and remove the 13mm nuts holding the bolster in place. Position the fan switch to high and turn the key to position 2. Using a test light, probe the large red wire on the two-wire fan connector and look for the test light to glow brightly. Adjust the fan speed and you should see a noticeable change in test light intensity. If your test light responds accordingly, time for blower fan replacement. If you aren’t getting any illumination on your test light you may have a bad final stage or climate module.

The final stage for Electronic Climate Control (ECC) controls the high power current to the blower motor based on the input from the climate control module. For vehicles with manual climate control (MCC) a resistor pack is used. When either ECC or MCC is set on high fan speed and also set to defrost, full current is applied to the blower fan, this can be useful as a diagnostic step to discern between fan or final stage failure. If your ECC has flashing LED’s on startup for around 20-25 seconds you have a code in your system. Many times a ‘high current code’ is set from a blower fan that is going bad and is drawing more current than normal. Depending on how much excess current the blower fan drew the final stage/resistor pack may have been damaged and need replacement.


Genuine, OE, OEM and Aftermarket Online Car Parts Catalog

IPD is the Volvo Parts, Accessories and Performance Specialists Since 1963.

We offer high quality replacement car parts, custom kit builder solutions, heavy duty parts, all with an unmatchable 50+ year reputation and customer service team committed to our clients. Our custom built online parts catalog features Genuine, OE, OEM, and IPD branded replacement parts for Volvo vehicles.

We are truly unique with a reputation that spans over 50 years. Not many others can match our knowledge, dedication to high quality products and providing the very best customer service in the market. We have a physical location, live customer service agents you can call and inventory to ship products to you quickly. Our customer and vehicle first approach means that your experience is our first priority. We have truly hassle-free returns and provide do-it-yourself (DIY) guides and videos for many of our products.

We carry quality parts in a wide range of OES and Aftermarket brands including Akebono, Behr, Bilstein, Bosch, Mahle, Mann, Elring, Corteco, Hella, Sachs, Denso, Behr, Bendix, Brembo, Centric, Girling, Meyle, SKF, Koni, Lemförder, TYC, Nissens, Genuine Volvo and many more.

Through our other website WPD, we also offer replacement parts for Audi, BMW, Mercedes-Benz, Mini, Saab, Scion, Subaru, Toyota, Volkswagen and more from a large number of manufacturers.