what could cause a repeated problem of blower motor resistors going bad? since I've had this car I've had to replace it three times... and I've never had a problem with them in any other car. now the third one just went bad and I want to isolate the problem before I buy a new one. I wonder if there's a problem with the heater fan? maybe pullin too much current and causing the resistor block to heat up and burn? I dunno, but no parts stores carry them and I have to go through a dealer, at upwards of $30 for one. (of course, the dealer wanted over $22 for a thermostat when the $5 one I got from my store was defective... I'd never pay that much for a thermostat.. when they quoted me that price I damn near fell over!)

 

99% of the time when there is a repeted failure of the blower resistor it is due to a bad blower motor.
Like you said too much current draw

 

Unbolt the heater fan assembly (3 bolts, if I remember correctly) and then clean the squirrel cage fan of dust, etc. You can also try to take apart the motor housing and clean the inner contacts. Dust is a killer. If all else fails I have a motor from my '87, which I finally had to replace about 3 yrs. ago. I am parting the car out and will sell the whole assembly with resistor, fan etc. for $30 + $10 shipping.