I've seen multiple blower resistors where the resistor coils were fine--the thermal limiter had popped; and that results in no blower except on high speed.
No doubt thermal limiters are available from Digi-Key, Mouser, and similar electronics stores. I wouldn't know what specs to ask for, though.
Just for the record...
I had one of the thermal fuses cause a blower fan issue on my 1995 S10 recently (picture of its resistor assembly attached).
It uses three (3) of those thermal limiting fuses. Visibly / physically, they appear akin to a low-amperage diode or small-wattage resister. In fact, when I first saw them I didn't recognize them / know their purpose.
These thermal fuses should measure ~0 ohm when they're "good".
On my S10, all three were rated at
152degC (look for the marking "Tf" on the barrel of the device for its temp spec, i.e., Tf 152C). There may also be an amperage rating on them, but I didn't note it.
On the S10, the blower motor's operation depends on which fuse(s) are good. Any of the "speeds" other than "high" might be impaired or remain operational, it depends on which of the three fuses remain functional.
Here are some available on eBay as of now.
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