My auxilary fan on a 87 420sel does not run at all. What I did with ignition on; jumped #1,#2 connector on top of thermostat, fan does not come on. Jumped wires from switch on dryer, fan does not come on but I hear a "click" in the fuse box (ac controll unit?). Jumped the lower connects on the dryer unit, nothing. I did jump the fan direct so I know it does work. Fuses are good. How can I test/jump the C and D high and low speed relays to see if the fan turns on? And one last thing could this be a burnt resistor located below the fuse box area? I jumped from the positive batt to one side of the resistor, nothing, I jumped the other side of the resistor and the fan turned on high.
JD