The Mercedes EPC gives a good cut-away view of that area. If the blower motor is accessable (I have NO idea on a 107; is on a 126), seems like you might be able to use a magnet probe "upwards" and "rearwards". Good luck.

Seems from the EPC pictures that the blower is forward of where your knife would be.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)