It worked fine and then just stopped blowing on any speed. The #303 relay was swapped with another and made no difference. The #101 40 amp fuse checks good. The blower fuse under the dash checks good too. The actuator moves the flapper door as it should.
I suppose it could be the switch, but that requires some dismantlement of the dash.
When a blower relay goes bad, it will usually allow (in fact cause) the blower to go only on high. If it doesn’t blow at all, can that still be the cause?
There’s usually a blower motor resistor pack that allows the fan to go at different speeds. Usually when the resistor pack fails, only the lowest speed is affected. I’m assuming all the blower speeds are a no go, right? hmm … well I think it is still possible a bad resistor pack could cause all the speeds to not work. So that’s a possibility.
If this happened to my Corolla and I’d already did what you have with no luck, I’d be inclined to remove the blower motor and use a DVM to probe the voltages at the connector. If the voltage is there ok at the connector (with the motor plugged in), and the blower doesn’t blow, that means the blower motor is faulty. When you do this you may find the reason the motor failed, a bunch of leaves and twigs has got sucked in and stuck in the blower fan cage.
Have you verified that power is being provided to the blower motor itself?
Does this car not have EATC (Electronic Air Temp Control) on it?
If it stopped completely all at once I’d start (after checking fuses, which you’ve already done) by removing the fan motor and bench testing it. I’ve tested them using a simple 9VDC transistor radio battery. That’ll spin a good heater fan motor with no problem.
It does NOT have electronic air temp control. It’s a former police car which probably has a lot of idle hours on the fan while waiting for someone to do something naughty. I had not thought of that aspect. It only has 92K miles, but 43XX hours on the idle clock.
I’m hoping that the blower motor itself is not the culprit. I’ve never seen one quit suddenly like this. Usually they scream and whine in complaint for several weeks and die slowly.
I won’t have access to the car again until Monday.
That’s true about the normal failure mode for fan motors. On the other hand, it’s easy and definitive to check. Assuming, of course, that one’s body is still pliable enough to squiggle under the dash and get at the ductwork. In which case you have my envy. {
A blower motor can quit suddenly. What I would do is access the blower motor and disconnect the plug. Check the plug for burning as that is a common problem and Ford I believe even offers a pigtail repair kit for this problem although it can be worked around without going through Ford.
A burned plug is caused by long term operation of a blower motor that is dragging.
Just took a quick look and even AutoZone shows a replacement plug if needed.
The EATC models can suffer the same problem although a blower speed controller module comes into play there. Sometimes the modules can overheat and melt a bit for the same reason; a dragging blower.
Just a note about blowers. A few years back my wife said the fan had quit in our Lincoln but came back on after a few minutes. When I checked it the fan was blowing fine and making no noise.
I dropped the knee panel and put an ammeter into the blower motor circuit.
On HIGH speed that blower was pulling 27 amps and needed to be replaced.
Wonder why the wire plugs burn… 
2010 Crown Vic with a bad heater. I think it’s time to dump it. What do you want for it ? 
I just checked YouTube and found that it’s not one of those “stand on your head under the dash” blowers. That’s the part I was dreading most. The last one I replaced cost me two weeks of bad back pain. Yes @thesamemountainbike, I understand the dilemma.
Here’s how the blower is done, if the wiring going to it is not the culprit.
https://www.youtube.com/watch?v=Ja4dAjFk5Jk Yes, the guy has to twist a bit, but at least he’s not standing on his head.
And here is the blower resistor.
Thanks guys. I always tend to turn here first in times of adversity. It looks like it’s not that big a deal.
Have you tried tapping on the blower motor to see if it starts? The brushes wear at an angle in these motors and eventually, even though there is plenty of meat left in the brushes, the angle that they try to sit at causes them to get stuck in the brush holder. A little tap will temporarily move them. These motors are riveted or welded together so brush replacement is often not possible.
I had the blower suddenly stop on a Ford Aerostar I once owned. It didn’t work on any speed. I tapped on the blower motor with a screwdriver and it immediately came on. For a while, when it quif, I could open and slam the hood and it would start running. I finally replaced the motor.
I just got a chance to see the car again. I tapped on the blower motor with a very small ball peen hammer. It took right off. Looks like I have two choices. Either replace the blower, or buy a successive line up of heavier and heavier ball peen hammers.
Thanks four your input.
@MG_McAnick – Go the ball peen hammer route. The hammer is useful for a lot of things. The blower motor serves only one function.
I’ll keep that in mind @Triedaq. Who knows what other things might benefit from being beaten on?
Probably the brushes on the motor are worn out. My suggestion, new blower motor, after checking connections of course.
Yes, sounds like the blower motor brushes are worn out, or the armature contacts are oxidized or coated with gunk. If you can’t find a source for a replacement motor, a local auto-electric shop could probably fix it for you, replacing the brushes with new ones, cleaning the armature, and they’d probably install new bearings for you.
Reminds me, I have an electric toy train engine that needs this same treatment.
Unfortunately @GeorgeSanJose the motor does not appear to be serviceable. Like so many others, it’s a toss and replace item.
Given how inexpensive blower motors are why would anyone service or repair one?
Right.
I used to repair them, $3 for brushes and about a half an hour in time, but todays blower motors are either welded or riveted together so its R&R (remove and replace).