The blower in my car suddenly stopped working. I've tested the motor - works fine. I've tested the connector - varies from 0 to 12V, depending on the fan switch setting, as expected. I checked the relay. Works fine.

So what the heck is going on?!! My only guess is that there's insufficient current, but how can that be?

 

Probably a bad blower resistor on the blower assembly

 

Mine did the same thing last year. wasted all my time going finding another one at the Junk yard, still didnt work, Turned out too be the breaker on the drivers side Kick pannel, there is one for the defroster and heater fan.. Mine MELTED. check that first,

 

Checked the breaker and even swapped it with the defroster...no go.

Looking at the FSM, there's plenty more to check than I thought, but at this point, I'm guessing it's the "fan amp" that sits on top of the logicon. Assuming this item does what it sounds like it does, a dead amplifier would probably explain why I have voltage, but seemingly, no amperage.

 

Edit: Nevermind, you said that you tested the motor itself. I'll just leave my reply here in case someone else ever stumbles across it.

Take apart the blower motor and make sure the internal connections are good.
Mine had a bunch of moisture in it at some point and rusted out the springs which broke apart and the sliders didn't press against the center cylinder to make the electrical connection. I had to get a new pair of springs and clip them down to length.

Just one of the things you may not think about checking.
I made a thread at the time I did it, but all my pictures are gone.

 

Is the 12v getting to the motor? If so its not the amp. If you have voltage, you should have amperage, unless there is a short. So if you have voltage and no amperage, look for a short.

 

I'm going to run through the MANY steps in the FSM today, but yes, 12V is getting to the motor. I tried 12V from the harness and a separate ground and that didn't work either, so it's not a broken ground. When I connect the motor straight to a battery, there's a nice big spark meaning the motor pulls a decent amount of current, but when I connect it to the harness with the fan control on high, there's nothing of the sort. I'll agree that it could be a short, but it would have to be "the perfect short" to not pop the breaker, still give me 12V at the harness, but not turn the motor at all!

 

Wow, this problem is bizarre! If I follow the steps in the FSM, I don't get past the 2nd step with a result of "replace fan motor". So then I pull the probe from my meter, plug the connector back into the fan, and it starts spinning! Turn the fan control down from max, and it stops. Turn it up to full and nothing. Turn the key off and back on again, and it starts running again. I tested the Ex-Hi connector (which does what, exactly?) and it fails, which tells me to check the fan amp, which passes.

Anyway...I'm going to get my hands on a fan and a fan amp and I'm hoping one of these will solve the problem.

 

For anyone interested, I finally tracked the problem down to a bad power transistor - the one that sits in the path of the incoming air to keep it cool. Naturally, this part requires the most dissassembly to access. 'Tis always the way on this car!! I think it just enjoys me spending time with it, so it does everything possible to extend that

I picked up a complete blower assembly that was supposed to be off a '90 TII, but it was VERY different from my '91 NA. The plastic case was the same, as was that transistor, but mine has none of the other parts scattered around the other. No resistor, for example. The only items on the harness are the aforementioned transistor, main relay, Ex-Hi relay, and blower motor connector.

And now, of course, the A/C doesn't work! But that's more than likely not-related. I probably (make that hopefully!) forgot to re-attach the connector under the hood.

 

Hmm, just like I said...

 

You said:
Close, but no cigar. A resistor does not a transistor make!

 

sure you didn't confuse the two???

 

Positive. I know a power transistor when I see one, but if nothing else, a transistor has 3 'legs', and a resistor has two. I believe there is a resistor on the outside of that '90 assembly I mentioned, and maybe that's the one you're referring to, but that part just doesn't exist on my '91 assembly.

But the part sitting on a big heat sink inside the blower assembly is most definiately a transistor.