Glad you got it going. Too bad they integrated the motor so tightly after 1980. I remember reading somewhere that you could use a 78-80 motor on the later cabs... Maybe I'm having a senior moment too.
Circuit 93 is actually White but I bet 33 years have turned it yellow.
Pink is ground from the switch.
Chilton is a one size fits all diagram that's mostly almost but not always correct.
The 1983 GM Light Truck wiring diagrams PDF in the 73-91 RTFM link below has the correct colors. I thought you'd have a hard copy.
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1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8
RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.