Anyone with good auto knowledge?

[Dustin Lane]

I'm having some issues with my volvo's blower motor. It started out being really finicky, not working on some days while working on others. With the cold weather it has become more just not working at all. So, not wanting to throw more money at this car than has already gone into it, I'm trying to solve this myself. I have replaced the blower resistor pack, but still have problems. While outside the car running on 12v the blower works wonderfully, faster than I've ever seen it run before. While mounted inside the the car it doesn't run at all, or runs very slowlys. If I have it hang down, held in my hand, in the passenger foot area it will run at about 50% for a few seconds and then slow down to an almost stop. While mounted if it does run it will squeak, but doesn't do this outside the car.

To me this makes it seem like the blades are jamming against something inside the mount. However if I unscrew the motor and back it out a little the squeaking persists. Playing(pushing it forward or backward) with the power connector I can make it squeak more or less.

I doesn't seem like the blower is shot since it works perfectly outside the car but I don't get what putting it inside the car would change.

I've done a huge amount of searching elsewhere on the internet and have yet to come across a solution. As of right now I am blaming the swedish curse. Any help would be great.
It's a 96 vovlo 850 wagon with auto climate control.

Many thanks,
Dustin

[Greg Peterson]

Check for a bad ground? Bad switch or relay.

If the motor runs fine on exterior power then something is compromising the motors power supply.

Hook up a multi tester and see how many volts and amps are available at the motors connector.

[Ben Rafael]

I had a 99 Volvo where the blower motor had a mind of it's own. Started and stopped seemingly at random, Even with the power off.
My Volvo did a lot of weird things. It's not a curse, it's a Volvo.
I sold the damn thing last year. It was a comfortable, pleasant car to drive, but I will never buy another Volvo.

[Tom Godley]

It from what you are describing I would think that one or both of the motor bearings are bad.

The motor should not squeak -- and it should not slow down or stop with a change in the position of the motor.

The motor shaft may be moving enough to allow the armature to hit the inside of the housing.

If it is not too bad you may be able to place something like a white lube - that will stay in place -- but I think you should starting to look for a replacement.

[Pat Germain]

I agree with the switch theory. If your Volvo isn't very old, you should be able to buy a new switch from the dealer. It won't be cheap, but I bet it would fix the problem.

If you got a switch at a salvage yard, there's a good chance the replacement would have the same problem.

[Dustin Lane]

Check for a bad ground? Bad switch or relay.

If the motor runs fine on exterior power then something is compromising the motors power supply.

Hook up a multi tester and see how many volts and amps are available at the motors connector.

Sounds like this will have to be my next step. After this, maybe a salvage yard will let me do a test run with one of their used motors. From there I'll have to try out switches.

Thanks for the replies.

[Tom Godley]

Maybe I missed something -- when you have the motor out of the car and connected to 12v will it run at full speed in any position.

The Volvo ACC I had in the mid 90's had a step power supply -- it was controlled internally through relays . I believe it had 4 speeds plus full. They powered out to the resistors.

[David Freed]

Concerning the sqeak; when you try it outside of the car, are you holding it in the same position that is in inside the car?

[Dustin Lane]

Maybe I missed something -- when you have the motor out of the car and connected to 12v will it run at full speed in any position.

The Volvo ACC I had in the mid 90's had a step power supply -- it was controlled internally through relays . I believe it had 4 speeds plus full. They powered out to the resistors.


Correct, I had the motor out and was running it off of a 12v line from a computer power supply. Ran full blast in every orientation.

One thing about this automatic climate control junk is that it has a special powerstage resistor set thinger so it has a slide bar and then it has automatic control where it takes temp readings and then controls itself based on the current temp and what temp you want. So no there's no easy set number of resistors. Personally I think a lot of new 'features' become nothing more than one more thing for me to fix.

[Tom Godley]

I happen to really like ACC in a auto - but they are complicated -- and information can be limited outside of the dealer network.

If the motor works outside the car when connected directly to 12v and in all orientations then it must be OK. It should be easy to see if anything is hitting inside - I am sure you looked. I had a problem with a power vent actuator one time that was caused by a deformed heater box. The heater matrix became so hot it slightly deformed the box jamming the vent. You could check to see if the motor is being twisted as you screw it down - kind of a long shot!


Often these units have a common point that fails. All the older MBenz units were always in the pushbuttons -- The Porsche/Audi units all blow the controller pack. But you did say you did a search -- and the pack was replaced ??


Sorry I can not be any more help.

[Dustin Lane]

I do like the ACC too. I was thinking more along the lines of those headlights that turn when you turn a corner. I can imagine those getting stuck in the wrong position or something stupid. Or rear view cameras, I'm all for more tech in a car but really? we can't turn our heads backwards anymore? Maybe they give a better view, I dunno. I just enjoy complaining sometimes.

The rubber gasket around the mount is a little worn on the top side and so I thought that might be twisting it as it got screwed in but adjusting the screws didn't help, so I don't think its that.

[Dustin Lane]

A bit of wd-40 here and there, some sanding on the fan blades and the opposite side of the blade and she's as good as new!...well, everything works again so I'll leave it at that.

Total spent was 3.50 for the new MOSFET chip for the resistor pack and a bit of my time. Can't beat that at all considering the mechanic would have cost somewhere around 100 fold more.

Thanks for the help everyone.

[Prashun Patel]

(From a friend)

Replacing the resistor pack was a good idea and it can't hurt. I would suspect inspect the squirrel cage fan and housing for jamming. If nothing reveals itself then change the fan and motor, because something might be slightly jamming which you can't see and the motor is old and might deliver the full load it should.
I also had the same problem in my 92 740 and solved it by replacing all three things.

[Lee Schierer]

Years ago I had a Toyota that had similar fan issues. I finally tracked down a cracked fuse in the fuse panel. The crack in the fuse caused a poor connection and the fan didn't perform well. DC motors have brushes and it could be that yours are worn or the springs are not pushing the brushes against the commutator creating a poor circuit. It could also be that the thrust bearings are shot and the armature can move depending upon orientation.