Dead Motors Relay and Switches can be a symptom, not the root cause.
See my Cave,
Electric Motors and
Wire ServiceOften the Rad Fan have crap ground
and crap power because red wire have to go thru several connections before get to the relay and relay may be dying too.
And I mean Ground. Fan Ground uses same screw but is Not shared ground w/ HL etc and only connects to frame near left HL assembly. Is a bigger wire then other too.
Add most GM FWD and Fiero Rad Fans was never made to run all the time. Adding switches or shorting out the green control wire can shorten the motor(s) life a lot.
Yes, Fiero AC control head does same but GM didn't care if fan dies after Warranty ran out.
Heater Blower Motor can have a short life when run a max speed too. Both are nearly identical design and made cheap as possible.
If you think aftermarket fan/blower motors are much better... Most of them are same thing hating to be on all the time.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave