After you replaced your blower motor in your 1989 Oldsmobile 98 the blower motor still ran with the engine turned off What may be the problem?

I had the same exact thing happen on my '89 Olds 88. It is the blower control module. Please don't don't confuse this with the resistor or relay, or even the delay module. It is simply called the A/C blower control module, and is usually located under a plastic flap, on the firewall, near the passenger side of the vehicle. I was a parts man at a GM dealership for 18 years and, if my memory serves my correctly, the GM part number will most likely be 12484912. It's not the simplest of operations, but if you have any mechanical ability at all you should be able to do this yourself.