Test the fuse and make sure is has power.
You can apply power directly to the aux fan to make sure it does run.
As Steve suggested ground the 212F switch and by pass the high temp switch on the receiver drier (Yes Spiderman, this swicth is a temp switch unlike the new ones we have ).
Check the freon level in the A/C system also.
HTH

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Scott Diener
89 300E
93 300E
92 Volvo 740 Wagon aka "Mutt mover"