I've had those exact traces burn out several times on my 83. I've replaced the blower motor, unplugged the AWP, replaced the mono valve, upgraded the fuse and wiring to the blower.

I have a buggered ignition switch. if its been the ignition switch the whole time....

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77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

You need a new monovalve...not the kit, but the entire item.

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Pierre Hedary 1985 280SEL, 1970 111.026 in progress
Mercedes technical advice hotline: 407 765 2867
[servicing older Mercedes in the state of Florida with competence and passion].

From the standpoint of an honest MB technician, Vegetable oil is a threat to your diesel engine's mechanical integrity.