1997 E430 heater blower inop
 

Hi can anyone direct me in the correct direction i have a E430 1997 and i have no fan speed at all the heat / defrost comes out and the graph on dash control is at max or any speed and still no fan at all -- jz

Check for voltage at the fan. If present, disconnect the regulator and ground the fan lead. The fan should run at full speed. If not, the fan motor is at fault.

If so, check for voltage at the regulator input when there is full demand. You should have 6 volts there. If so, the regulator is almost certainly at fault.

Mine does the same thing, only is intermittent. The brushes on the sealed motor stop in a dead spot; pulling the panel and fan motor cover and reaching up into the squirrel cage and giving it a counter clockwise turn confirms if it fires up.

Fan motor unfortunately is sealed.