Bad temp sensor for the fan. If it's working OK in synch with the AC, the other actuator for the fan is the aux fan temp sensor. Located on the right side of the head near the back. Why is your car going into the red? Be sure the thermostat is properly installed and working. Your radiator may have a problem if the t-stat is OK. The actuator for the AC side of the circuit is pressure actuated. When you say kickdown cable are you referring to the pressure regulator cable attached to throttle linkage. If so, not to hard to replace.
1987 BMW 325
[This message has been edited by jeffsr (edited 06-19-2000).]