On 1992 940GL (187K) blower will run for a bit and then the fuse blows. Replaced the blower switch in the ECC with a used part but the fuse problem continues. The old switch worked, but for some time had been "continuously variable" instead of having 5 discrete settings. Have read that a failed Blower Motor Resistor can result in the fan only running on position 5. (I'm wondering if the crippled switch could have degraded the resistor over time). In this case, after replacing the switch the fan runs on all 5 settings until the fuse blows. I'm also wondering if it might be related to running the AC, I noticed on three occasions that the fan ran fine for extended periods but the blower fuse failed shortly after turning on the AC. (Note - the AC button failed a couple of years ago and a mechanic installed a toggle switch on the dash to activate the AC to avoid the expense of replacing the ECC). Is the blower motor resistor tied to the AC circuit or just the blower? Do you think it's a bad resistor, a bad blower motor, a problem caused by the AC or toggle switch, or something else?