Actually the blower is very easy on the 126 chassis. It is above the passengers feet.
You will need to remove the plastic underdash panel and it is mounted into the bottom of the evap housing closer to the outside than the center.
A very common lack of blower problem is caused by the ignition switch. Try starting the car and wiggle the key back toward off. If the blower comes on you are done with diagnostics. If this simple test provides no answer go to the blower and test to see if there is battery voltage and ground on the two wires going to it (easily available without removing blower). If you really want the sure answer disconnect the two wire connector and put one wire to ground and the other to 12v. If the motor is good it WILL run. You don't even need to worry about polarity as the motor will run in reverse direction if wired backwards The test is still valid. Just be sure to wire it properly when done.
Bosch Master, ASE Master, L1
33 years MB technician