a friend brought me a 93 240 wagon to diagnose whose blower motor abruptly failed on him.
one day it ran perfectly the next day nothing.

here is my story how i found the problem.

1. a fuse check to #3 reveals a good fuse
2. i loosened and pulled back the center console facia after removing the blower knob.
3. removed the connector which attaches to the blower switch.
4 using a test light with the positive probe inserted into the white/black wire fitting on the connector and the neg to ground i switched the key to the 2 position. the light lit indicating voltage directly from fuse 3 intact.
4. using the ohm meter function of measured ohms between slots on the connector 1 and 2... 2 and 3 ..... 3 and 4. all measured within proper specs indicating the resistor is functioning correctly.
5. lastly i jumpered the black white terminal on the connector with the red output terminal to the motor and put the key in the 2 position......nothing...no motor function at all.

at this point i concluded WRONGLY as it turned out the motor was dead and proceed to dismantle the dash board to replace the motor. after nearly 4 hours of this task the motor is now exposed with only the 3 screws holding it in place so i remove the push on connection between the motor and the resistor harness right on back of the switch which by the way takes a few minutes at most to access. this push on connection noted by the red circle is quite difficult to remove. once off it becomes obvious why.

the plastic and part of the metal female housing coming from the switch side of the connection has melted and burned impairing voltage flow to the motor.

applying 12 volts from a jump pack directly to the red wire leading to the motor
and grounding the negative causes the motor to run instantly.

problem found and solved with only 3 hours of re installing a large part of the crap in front of the drivers seat back into place.

the lesson: remove the push on connector (red circle) soon into diagnosis phase should the motor quit abruptly. it is largely hidden by the plastic and can fail without any outward indication. as to why it failed i have no idea. if anyone can point me a way to further test this i am grateful.