I finally tracked down the problem with my car’s defrost system. It is the blower motor-all the other controls (dash control, power relay) check out OK. My proof is the motor will run given a sharp rap to the case.
I suspect that there is a “dead spot” on the commutator-or the motor brushes are worn beyond good contact. I can replace the whole unit.
But this offends my desire to fix things-is there any way to repair such a motor? or are they sealed and impossible to fix?
Ralph, blower motors also have a strong tendency toward heating up connections leading to a lot of resistance in the circuit. I would first inspect the connections. Not sure where you would buy parts if you needed them to repair the motor.
Often times you can drill a small hole in the housing and put in a drop or two of zoom spout to free it up. I haven’t tried it myself but the last time I was replacing a motor I had two friends, separately, tell to do it. One of them used to fix machines in a huge factory. The other one fixed a similar motor to mine that way about a year ago and it’s still running. Of course this is only going to work for certain problems. If the bearings have fallen apart or the windings are shorting out its not going to work.
Generally they can be rebuilt by facilities equipped to do so, but they are not designed to be repaired in the field, and whatever parts would be needed are not available through auto parts suppliers.
Thanks…the car is only 7 years old. But I suspect that replacing the whole thing is the better course of action. I think that the unit is sealed and not designed to be repaired.
Another example of the 'throw away" mentality.
I like to fix things too,I just don’t like to have to do it twice. I’d rather buy a new motor and not take the chance that a repaired one will fail a month later. That’s not to say a new one can’t fail but the odds are better it won’t.
If you can even remove and replace it, there is an engineer somewhere who has not done his job properly - they are also supposed to be inaccessible as well as unrepairable…
Unless the duct is clogged to the point that the fan is bogged down, about the only motors that are still designed to be rebuilt are the multi-horsepower units in commercial/industrial equipment.
I don’t know if home furnace/HVAC blowers are still repairable - with the multi-speed windings, they probably aren’t.
Do any mootrs still use carbon brushes? Those were the only pieces short of an armature that could be replaced in a fractional-hp motor.
WHAT ?
Of course you can replace it ??? It can be repaired, but its factory stamped together for simplicity - weight and space is at a premium.
Yeah the brush may be stuck or worn down. You might be able to do something simple, like turn the brush 90 degrees and use a cable tie to hold it place.
In my experience, it seems most cars start life as the heater assembly, and then they build the rest of the car around it as tightly as possible. :smack:
For some cars, but as Click and Clack would say “If you’ve lead a good clean life it’ll be easy” on my old Chevy Cavalier the blower motor was sitting right where the passenger’s feet are. Dropped right out. Took me all of 15 minutes to pull it out, put in a new resistor, and put it back on. On our Ford Bronco it’s right on the other side of the firewall for all to see. Three small bolts and other then dropping the socket on 6 inches of snow and having to spend 45 minutes trying to find that, the rest of the project took about 15 minutes (replacing the blower motor).
On some cars I’m sure it involves pulling a section of the dash.
Replace the blower motor with one from a parts place. Then unless there is a core charge for the old one, mess with it. If you can get it working, put it on the shelf for about 7 years when the heater goes bad again.
BTW: If there is a core charge (where you get money back for returning the old part) then there’s a very good chance that it can be fixed, but it probably takes some special tools to do so.
Like the OP, I like repairing rather than replacing too, but a core charge would be the next best thing. As long as someone is repairing it, works for me…
My BIL’s blower on his Explorer died. Fiddling and BFH got it spinning again, but its days are numbered. I ordered a new one online for 65 bucks, with free shipping.
It will take about 20 minutes to install, and he’ll be warm on the job site again.
YMMV.
The most likely culprit to my mind is the brushes in the motor of the blower are worn down and not pressing hard enough to the commutator.
So, first you need to pull the motor and see if you can access the brushes which is highly unlikely.
If you can pull the brushes, then you must order them which is likely impossible.
If you get that far you might find it still doesn’t work
Just get a new blower. That is what the shop would do.
I work for an automotive parts manufacturer (we also dabble in reman). Assuming it is truly a bad motor, and not something simple, like the resistor pack, I am sure its “possible” to repair the motor at home, BUT if it is anything like the motors that we supply in our electro-mechanical components, you’re going to be much better off replacing the whole unit. Both in terms of cost and time.
Many automotive componnents are assembled with methods that are not easily reversible. Components are overmolded in plastic, bearings are pressed in blind holes, leads are welded, motor housings are welded, covers are glued, etc. Or they simply require specialized tools.
Additionally, the needed replacement parts are not available to the public as component parts.
Considering those factors, even though you may be able to work-around, or rig the motor to work, it would not be worth it in the long run. If there is a core charge, then you can rest assured the old motor will be sent to a facility like the one where I work, and things like brushes and bearings will be replaced, commutators machined true, reassembled, tested, and sent back to the dealers. Things that cannot be disassembled or re-used, will be sent to the recycler.