Vents Blowing Warm Air

[AzHotLS]

With my AC temporaily on vacation, and the evening temps finally getting cooler, I notice my vents still are blowing warm air.

I have the vents set to fresh air, temp set to 65 but it still blows warm air. So much so that I just leave it set to recirculate and no fan.

wwest posted this in another thread

The Lexus climate control, absent being in max cooling, uses a reheat/remix method wherein ALL of the system airflow is first chilled via passing through a COLD A/C evaporator and then a selected portion (ALL, in the case of max heating) is diverted through the heater to be reheated. Both portions are then remixed resulting in air outflow that is not so cold as to be discomforting but still cool enough to eventually cool the cabin down to the temperature setpoint. As the cabin reaches your temperature setpoint the system airflow, in cooling mode, will sometimes be only about 2F below the setpoint.

But I'm not using the AC or anything, just fresh air. Why are my vents blowing warm air? Am I still getting some of the air diverted through the heater? If so, is there a way to stop that?

[wwest]

"A/C temporarily on vacation...."

I assume you mean something about the "A/C" has failed making it inoperative...

IN the meantime you can check the positioning of the reheat/remix vane inside the plenum by checking the push/pull cable that operates the hot water valve inside the engine compartment at the top center of the firewall.

Going from max cold to max hot should result in the cable moving the hot water flow valve from fully open to fully closed. With the valve fully closed the mixing vane servomotor should be positioned so no air is reheated.

[sha4000]

more than likely the outside air is mixing with the heat coming off the engine

[nc211]

I agree with sha400. Mine does this too and I have no problems with the heat / ac in my car. Well I probably will now though since I'm sure I just jinxed myself.

[AzHotLS]

"I assume you mean something about the "A/C" has failed making it inoperative..."

Yes, the compressor has a leak and am going to replace it soon, in the mean time it's windows down and roof open.

I turn the blower on and raise and lower the temp, when I raise it, the servomoter does it's thing and the air gets hot, lower the temp and the air gets cooler again. So that part seems to be working to some extent. However, it's still not as cool as the outside air. I know it will be slightly warmer as the ducts and all are warm from the day and will warm the air slightly. But it's still too warm to let air come through the vents.

I haven't looked under the hood yet to see if it's closing all the way. I'll do that and post back.

"more than likely the outside air is mixing with the heat coming off the engine"

Isn't the outside vent grill seperated from the engine compartment?

[sha4000]

the vents are close to engine it doesnt matter

[AzHotLS]

The hot water flow valve is opening and closing all the way. Is it possible that it's still allowing water to flow when closed?

[wwest]

Remember that the cooling effect of the "breeze" from the A/C blower is the result of the evaporation of your skin moisture, perspiration. If the humidity of the "breeze" is already quite high, ~70% and above, not much evaporation will occur resulting in your just feeling a warm breeze.