Fuel pump is not turning off even with key out

1995 nissan 300zx fuel pump runs after turning key off, have to pull the wire off to stop it. Is it a bad relay or ecu, if ecu how would you check it? Just had the blend door mode motor go out with the vent in defrost position had to take to Nissan dealer to fix and found they cannot get the part anymore, discontinued and nobody sells a replacement, so I had them remove the motor and fixed the linkage in the A/C vent position. When I got it back the seat back would not move turns out the switch is getting bad contact and had to wiggle it to make contact and then it worked. Two days later I pull in the drive and turn off the key and hear a humming, found the fuel pump still running and would not stop. Pulled the bottom wire off the pump to stop it, plugged back in and still ran. Pulled wire and left off. Side note; I pulled the mode motor assembly apart and found the dc motor had dirty armature, cleaned it and put back together and motor runs. Problem is the can is crimped and had to destroy the end bell to open up, plan on buying a dc motor from local hobby shop and putting back together. Do you see any problem doing this?