Not to long ago i made a thread where my heater didnt work. So i was advised to change the blower motor from users on this forum which i did everything worked again. I had went with the cheaper blower motor by TYC and not the OEM brand. Now four months later im having another issue everytime i turn on the heater i can hear like an alarm/siren sound going off in the engine, when i turn off the heater it goes away. Also yesterday when i had the heater running for a while i started to smell a burning smell coming from the vents, one of my friend noticed smoke also coming from the vents. Anyone knows what may be causing this?

 

Is it the siren or the sound of a bad blower dying?

Unbolt the blower and run it on the floor to see if it's the source of noise/smoke.
Maybe you'll notice melted wiring when inspecting the blower/regulator.

BTW, I think it is important that in the original thread your fuse was melted: https://mbworld.org/forums/c-class-w...rt-number.html
Is the fuse ok now? Did you get an OEM regulator or an aftermarket one?

If the fuse is ok, I am betting the motor is seizing and the (weak) regulator is starting to melt from the extra load...