Interior Air Temp Sensor

[SKperformance]

Ok i posted this a few years ago in the ES section and forgot about it.

So here is one for the LS guys ,although every Lexus has the same system just slightly different locations.

There is a sensor for ever auto climate control which has a interior temp sensor to tell the hvac control what temp it is so it can reduce/increase fan speed and temp adjustment.

On all cars it is covered by a small slotted piece of plastic usually by the drivers right knee on the dash.

How it works is the temp sensor is much like a MAF and is a small loop of wire which is heated/cooled to measure temps.

As the vents are on and are blowing they suck air through a hose which is connected to the back of the sensor. This causes the air to register a temp which is continuously monitored.

By air flowing over the wire it gets dirty and needs to be cleaned every year or so.

I was replacing some more interior lights today and remembered to check mine as i was in there.

It was covered with a 2mm coating of dust which basically renders the sensor useless. My car is 7 years old as well the hose connecting it had come off so it was not getting a constantly new air temp flow.

So to find it on my 98 i had to remove 2 Phillips screws to drop the under dash panel.

Then popped off the panel that surrounds the key cylinder , it comes off real easy with only clips(pull towards you). The undo the 4 10mm (one is covered by the key cover , the other is by the emergency brake release )bolts that hold on the knee panel on the dash.

Once it is off you will see the hose connected behind it that just slides off and a 10 mm bolt holding the sensor onto the panel.

I used a few shots of brake cleaner and a q-tip to remove and residue.

The wire is fragile so i would not recommend using the q-tip as it bends easily with it.

Once it is dry ,reasemble and notice the difference of the fan not always being at full speed trying to heat and already warm car.

It takes 10 minutes to to

5 10mm bolts

2 Phillips screws

a can of brake cleaner

[sha4000]

ill check that real soon

[kcpth]

i'll have to give this a shot too. Thanks

[j.barleycorn]

Unbelievable!

Just this afternoon I was cleaning the interior and for the first time noticed the small slotted opening you described and wondered what it could possibly be... then went back to blissfully conditioning my seats and forgot all about it.

Thanks for the tip, SK!

[SKperformance]

Well after 1 day and some semi cold weather i can finally go in my car and while it warms up the interior it is not blasting me with hot air thinking i am an icicle with the fan at full tilt

[SKperformance]

So any one check theirs?

I noticed if i open a door the sensor knows right away and will increase the fan speed to compensate the rush of cold air being ingested.

Also when it is on heat ,when the cabin finally gets warm it no longer gets cold as the dirt around the sensor is not holding heat like a blanket making the cabin cold again.