I heard a vibration/noise coming from under the dash of my 93 ls400 when the fan motor was on. Doesn't matter if the fan is on recirc or fresh air---or where it is directed. Popped the hood and there is a sensor of some sort on the firewall with a redish coolant hardened up on it--looks almost like battery acid. I tried to accuate the cable attached to the valve manually with no luck. What is this valve/sensor called?
I assume this is the vavle to switch from the recirc to fresh as there is a heater hose in and one out going to the heater core.


thanks for any hints

mark

 

Sound like a leaky heater valve. If you want to know if the actuator/valve is still movable, try setting the temperature to maximum & minimum.