alexp7

Hello CL. Ive been having a problem with the heat in my 92 SC 300. If I start my car cold and let it warm up to operating temperature the car will refuse to heat up. My temp needle sits right in the middle of the gauge. Five minutes into driving the car it will start putting out some heat. If I then stop driving the car and just let it idle, the heat will stop. Ive already checked the coolant level, the thermostat is new, and the vacuum switch valve. My blower also changes speed based on rpm of the engine. At idle it slows down. Never had another car do this. All help welcomed. Thanks

reodan360

It could be that your heater control valve may have went bad and the previous owner did the bypass fix.

https://www.clublexus.com/forums/per...rol-valve.html

I am also currently doing the bypass method because my hcv is bad. Try seeing if the hcv were rerouted. As for the speed of the blower, it could be that your hvac temperature is set to auto.

alexp7

Thanks for the reply. I checked to see if my vacuum tubing has been rerouted and it hasn't been. I will try it out and see if I get better heat performance. If that doesn't solve anything am I to assume that my "actuator" or heater control valve is bad?