Thanks to 04TBEXT - I followed your instructions and now my heater fan works great! That's especially important here in Michigan at this time of year.
One noteworthy item - the new resistor had a plastic rectangle on one side that made it impossible to install in original orientation
(we call this mistake-proofing in the industry). When I installed it backwards, the blower motor power wire wouldn't reach the motor. Also, the 7-pin connector would be practically impossible to remove if I ever did this again because the positive lock clip would be facing the firewall, not the interior.
I ended up cutting off this rectangle with a Dremel tool and installed it in the right orientation, and all worked perfectly.
Last note - you need a 7mm (I didn't check for a US equivalent) socket to remove the close-out panel and a 7/32" socket to remove the resistor itself. They are screws, but hex-headed, not phillips.