Rear seat heater not working 1998 lx470
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By rear heater you mean the heater core under the console next to the driver's seat ? The heat should exit at the feet of the second row passengers. Yes, that is plumbed with engine coolant and will always be hot.
I don't have rear air but my understanding is that the vents on the roof are cold air only. The second row heat will travel to the rear quickly though because the entire system vents through the stylish vent flaps at the rear of the truck.
Search for "heater" in 100 forum finds ...
rear fan - blows cold air only
Rear Heat not working
heater doesn't put out much heat (sprocket3)
I don't have rear air but my understanding is that the vents on the roof are cold air only. The second row heat will travel to the rear quickly though because the entire system vents through the stylish vent flaps at the rear of the truck.
Search for "heater" in 100 forum finds ...
rear fan - blows cold air only
Rear Heat not working
heater doesn't put out much heat (sprocket3)
Rear heat is through floor vent at center console, cooling is through the overhead vents. Make sure that on the rear HVAC control, that "auto" or "floor" is selected, or you will not get any heat to the rear.
I am not sure of the relationship, or if this helps, but I had a similar situation where the rear passengers were getting cold air blasted on them, even after sliding the overhead thermostat to bake. Finally we just turned off the rear air button on the dash to tolerate the rest of the trip. When I returned to figure this out, I saw that the AC button on the dash was lit (automatically), and when I turned it off, the air from the overhead rear vents warmed considerably.
Not a scientific approach, but I think that the rear thermostat is not as advanced as the front - meaning that the dashboard balances heat and cool to reach the desired temp from the same set of selected vents, whereas the rear is mixing cold from above and heat from below to reach the temp. By turning off the AC compressor, it becomes all heat. This was about 2 months ago so I will try it again tonight and see what happens.
Not a scientific approach, but I think that the rear thermostat is not as advanced as the front - meaning that the dashboard balances heat and cool to reach the desired temp from the same set of selected vents, whereas the rear is mixing cold from above and heat from below to reach the temp. By turning off the AC compressor, it becomes all heat. This was about 2 months ago so I will try it again tonight and see what happens.
Usually the AC compressor will run while in the defrost mode to dry the air. Could this cause the rear evaporator to get cold ?
OK I was totally wrong in my last post. Most vehicles automatically heat the rear seat floor area off the front heat system, but Toyota had to be different. The front and rear systems are isolated.
Ben (Firetruck41) is correct -
I have the overhead thermostat controls in the rear, rather than the console mounted version that some LC's have. On the overhead system, there is a thermostat setting as well as 3 fan positions and 3 air direction settings (floor, both, and head). There is also an AUTO switch. With the temp set to broil, and the air flow set to head, no hot air will come out, only room temp. With the AUTO setting, you can adjust the temperature and it will automatically change the airflow depending on temperature.
The third row simply doesn't get the heat unless you mix the air flow setting.
Ben (Firetruck41) is correct -
I have the overhead thermostat controls in the rear, rather than the console mounted version that some LC's have. On the overhead system, there is a thermostat setting as well as 3 fan positions and 3 air direction settings (floor, both, and head). There is also an AUTO switch. With the temp set to broil, and the air flow set to head, no hot air will come out, only room temp. With the AUTO setting, you can adjust the temperature and it will automatically change the airflow depending on temperature.
The third row simply doesn't get the heat unless you mix the air flow setting.
The 100 has an unusual rear heating system. The heat source is from under the front seats and supplied at floor level. The cooling (A/C) source is in the right rear corner next to the tailgate, and is supplied from the overhead vents. The temp control in the second row roof behind the driver controls the temp of both sources. Rear air on the 2001 is initiated by a button on the lower center dash. Since heat rises and cold air drops, this is an effective means of air supply. However, because the heat and cooling sources are separate, the supply is separate also - cooling only from the upper vents and heating only from the lower vents. Setting the control to Auto and a desired temp has been the best practice for me, with overall control from the on/off button on the front dash.
