1995 Volvo 850 - Heater/Cooler fan not working

sgm85 · Post by **sgm85** » 23 Nov 2010, 14:50

I own a 1995 Volvo 850 and live in the Palouse region (SE Washington/N Idaho). We moved here several months ago from San Jose, CA, where ourselves and the car lived our entire lives. It's about to go through it's first real winter (doing pretty well with a foot of snow and near-zero temps), but about a month ago the fan in the heater stopped working. This is causing problems on cold nights as the defroster does not work like it should.

I'm looking for a diagnosis more than anything, since we are planning to go across the state tomorrow and want to see if it's possible to fix before then, at a shop or otherwise. I've come to the forum before and have gotten "bad cable" as a reason as well.

Here are some facts about the problem:

- It initially did not work once, for one 10-mile trip. I turned the car off and then on, but forgot what the effect of that was.
- It was fine the very next day. It stayed like this for a week before failing permanently.
- The heat, cool, direction, defrost, and airflow still all work. When going over 50 mph, it feels like I have the heater on low, and the defroster actually does something, simply from the speed.
- When I turn the heater on high (4), a mechanism under the dash reacts, making a sound.

I'd love any advice on the problem, what I can do to fix it - any suggestions would be much appreciated.

Thank you!

Post by **vjaneczko** » 23 Nov 2010, 15:56

Do a search for (1) blower motor and (2) Blower Motor Resister (for the MCC system) or Power Stage (for the ECC). Tons of postings and guides.

Odds are good for our 850's that the motor will seize, causing the resistor (or power stage) to burn out as well. The main cause is that the fresh air inlet of most units do not have a filter installed, which causes gunk to fall onto the motor, causing the seizing. So, best thing to do is get a filter, motor and resistor/power stage. Some have reconditioned the motor which will save the resistor - if you catch it in time - but everything is probably on its way out.

Post by **Ozark Lee** » 23 Nov 2010, 16:15

If the blower doesn't work on 4 then the blower itself is bad and you have likely blown the fuse. Check fuse number 5.

As was earlier said, if the fan went bad a seized then chances are it took the blower resistor out with it. The resistor is about the same price as the blower but change the blower first and see if you can get fan speed number 4 going again since you can ruin a new resistor if you install it with a bad blower fan.

...Lee

sgm85 · Post by **sgm85** » 23 Nov 2010, 16:44

I wouldn't be so lucky as to have possibly JUST blown the fuse and done nothing more, right?

Post by **Ozark Lee** » 23 Nov 2010, 18:39

sgm85 wrote:I wouldn't be so lucky as to have possibly JUST blown the fuse and done nothing more, right?

I always like cheap and easy first but I am putting this one in the "Doubtful" column.

...Lee