1998 C230 interior blower fan won't shut off
 

This is even when the car is off and key is removed. Interior cabin blower fan still runs.

If I pull fuse 29 that is the only way to shut off the cabin blower fan.

A couple of months ago I replaced the blower motor regulator to fix a "no high speed fan" condition, and I changed the cabin filter too. All had been fine until yesterday when the fan would not stop.

Thanks for any help on this issue.