Blower Fan Stopped when Wife Hit a Bump

[mweiss]

My '98 Explorer's HVAC fan stopped working, according to my wife, when she drove over a rail crossing that was bumpy.

My first thought was a wire came off somewhere. So I checked to see if there was voltage at the fan connector. I pulled the 2 prong connector off and measured about 13.9V with the fan selector on high speed and the engine idling. Just to make sure, I got out a H4 halogen lamp and jumpered it across the connector, verifying that there was sufficient current to light the lamp.

Next thing I did was remove the top two bolts and pull back on the fan mounting plate to get a finger in there and see if the fan is stuck. It spins freely.

So now I'm puzzled.. motors don't typically just stop working like this. Is this REALLY a motor issue? I want to make sure before I order a new motor and go to the trouble of removing the air box, washer fluid tanks and that other gadget that hooks to the air intake via a cable. I probably can't do this til spring, as I don't have a garage and I have frostbite, so my hands go numb when it's below the mid 50s.

Also, where can I get a decent motor? The reviews on some of the motors I've found online say the replacement is weaker than the OEM. Sources for a real genuine new replacement would be appreciated.

 

[koda2000]

RockAuto - Motorcraft about $67 ( - 5% discount enter code MMEAJ18 in the "where did you hear about us" box at checkout). Prices for other brands start at around $20.

More Information for MOTORCRAFT MM844

1998 FORD EXPLORER 4.0L V6 SOHC Blower Motor | RockAuto

If your old blower is getting power (which you've proved it is) and has a good ground it should spin. If not, not much else it can be except a bad blower motor.

 

[fast_dave]

My '98 Explorer's HVAC fan stopped working, according to my wife, when she drove over a rail crossing that was bumpy.

I had the same thing occur as your wife experienced in a high mileage Chevrolet Colorado delivery truck (if memory serves me correctly, at least 230,000 miles)..

HVAC was on, drove across a LONG strip of railroad tracks within an industrial area, and the blower motor cut off.

Took out the old blower motor, opened it up, and found out that a combination of worn fan shaft bushings combined with a large build up of brush dust cause the brushes to stick slightly open, so that they could not come in contact with the commutator bars of the fan shaft. Add to it that the brushes were down to the the end of their length, which also meant that the compression springs behind them were at the point where they weren't compressing the brushes as well as they could (when new).

Replaced the blower motor, and all was well.

Hope that helps and I hope your wife says "told you so" ;-)

 

[mweiss]

Thanks for detailing what may have happened. I suspect that is the case here.

I have been shopping for a new motor, but the reviews on so many of the after market motors are poor. Can you recommend a quality motor that is a match for the original?

 

[J_C]

That would be the motorcraft from RockAuto that Koda linked. Among the others at Rockauto I'd be tempted to go with the SKP because it looks serviceable with the rear screwed on and an exposed bushing to lubricate it, but that exposed bushing also means it can become contaminated if you don't find a way to cover it up.

Then again, parts don't always match pictures. Once you go with a 3rd party supplier it could be anyone who makes it or they could all be selling the same thing despite pictured differences.

 

[mweiss]

There are actually SIX different motors listed at the Rock Auto link. The cheapest one is the motor plate and is about $19. But I have no idea if the motor is as good as the original.

I'm still waiting for the weather to warm up. In addition, I was diagnosed with Degenerative Spinal Disease and calcification of L2-L3 discs after the flu attacked an injury from 2007. So I'm getting around on a cane for a few weeks until the swelling in my lower discs subsides. Hopefully I will recover enough to be able to replace the motor in the spring.

 

[koda2000]

As I say previously, if you have good power and ground at the motor (which you've proved you do) and it doesn't work, there is really nothing else it can be except the blower motor. The bushes and/or commutator wear over time and then they stop working. How would you have expected an electric motor to fail?

I understand you wanting to know for sure that the problem is a bad motor. I hate buying parts w/out knowing that I've correctly diagnosed the problem.

If you want OE fan performance buy the Motorcraft blower motor. If you're more concerned about the cost, buy a cheaper blower motor, but other's have reported substandard performance from off-brand blower motors.

 

[MAS Tequila]

Try tapping the blower with a hammer or something similar.

Tap it, don't beat the crap out of it.

Mine got to the point where if I tapped it every time it stopped, it would work for a few more days.

It may keep yours going for a couple of days until you get to swap it.

Get the one that comes with the hamster wheel, sometimes it is a pain to remove the wheel without damaging it, they get brittle over time.

Do you have the EATC or manual controls?

If manual go ahead and change the resistor while the blower motor is out.

Otherwise good ol Murphy will get the last laugh and the resistor will go out right after you change the blower motor.

 

[mweiss]

I was debating with myself whether to get the motor or the whole assembly with the fan. Thank you for the warning about the danger of brittle and breakage.

I'm tempted to get the Motorcraft fan, although on that site, it is just the motor and back plate.
Is the fan press fit, or are there some sort of snap rings that hold it onto the shaft? I can Mystery Oil it to get it loose, I suppose.

As for the resistor, I replaced that a couple of years ago. It was under the dash, as I recall. I think the controls are manual, since it has a resistor in the duct.

 

[koda2000]

The squirrel fans I've seen have had a nut on the end of the motor's "D" shaped shaft and then the plastic fan is just a snug fit on the shaft. Be careful and you should be able to get it off w/out breaking it.

 

[MAS Tequila]

The couple that I did had a force fit kind of nut that was almost impossible to remove.

 

[koda2000]

The couple that I did had a force fit kind of nut that was almost impossible to remove.

You mean like the kind of nut that is used to keep the wheels on kids riding toys? If that's the case I'd either buy a replacement fan or maybe a blower motor that comes with the fan attached, or buy a replacement fan. RA lists two, says retainer clip.

http://www.rockauto.com/en/catalog/...at+&+air+conditioning,blower+motor+wheel,6560

 

[J_C]

Yeah, it's a good idea to try to get the old one off before ordering a new motor so you know whether you need the squirrel cage portion too.

 

[MAS Tequila]

Yes, the little slide on kind, just like some older kids toys.

 

[koda2000]

Yes, the little slide on kind, just like some older kids toys.

Those damn fasteners are nearly impossible to get off. I think that was the idea.

 

[MAS Tequila]

I had 2 like that.

 

[CDW6212R]

Ditto. Buy the OEM blower motor, and go very slow with the little clip that holds the fan blade on. I did that last Winter with my 98. Be ready with a vacuum cleaner to suck some fine debris from the AC evaporator. Most have stuff in there, mine were about half pine needles. I used a rubber hose and my shop vac, and spent a few minutes cleaning it out, before doing the motor.

I used a very tiny screw driver, and a handled pick, to get the clip teeth to come away from the shaft, and slowly worked it off. Go very slow, you almost have to bend it to remove it. You want to reuse it, so as long as you're gentle with it, it will work like new. The Motorcraft blower motor I got came with the gasket and little drain hose, nothing else needed but the fan blade.

 

[mweiss]

I put a new fan in from Rock Auto in May. It worked okay up until this week.

I just recharged the A/C compressor and went to test the air temperature and found out the fan is DEAD. I got one month of use out of it before it died.

Any ideas for a better quality blower? It's 97F outside and I am swealtering in this truck.

 

[mweiss]

Looking back at the original invoice I ordered the following:

MOTORCRAFT MM844 {#XL2H19805EA, XL2Z19805EA, YC358620HA}

But what I received from them was a "Brose" motor made in Mexico.

Their site said I cannot return as it's 91 days since the order, but I didn't receive it til April 6, so it's not yet 90 days.

So they charged me for a genuine part and sent me a counterfeit part.

 

[koda2000]

Call RockAuto and talk to them about this. In the past I've found they're customer service to be good. If nothing else, perhaps the part is still under warranty.