The fan runs at two speeds - low when triggered by a temp switch in the AC circuit and high when triggered by the coolant temp switch described earlier; the lower setpoint triggers the fan, the upper setpoint cuts the AC compressor. There are separate relays for low- and high speed. Low speed goes through the resistor you found. You can bridge the resistor for a single speed fan until you can replace the resistor.

Sixto
87 300D