I have a 1996 Lexus ES 300. What would cause the heater to work fine for awhile at a lower temp setting and then I have to turn it up to sometimes 85 or more to get heat. The coolant level is fine. Can anybody give me some ideas what could be going on?

 

Clean out the sensor under the dashboard that detects your cabin temperature.

 

Can you please help me out further with the lexus cabin heat problem? I looked on your Youtube videos and can not find the one for the cabin temperature sensor repair. Where under the dash would I look for that sensor on my 96 ES300?

 

Not sure that's your problem, but if you look under the dash, roughly inline with your knees, you'll see a little grill like opening about 1sq inch.

The sensor is behind it. Air is sucked in through that grill and into the sensor. All you need to do is to make sure that the grill is not obstructed. Use a vacuum cleaner to clear it.

 

You'll need more than a vacuum cleaner to clean your interior sensor. Mine was pretty caked with dust. It's also connected to a white hose that gets a lot of dust build up inside. I opened my sensor up and cleaned it completely. It feels like the HVAC response is better now with the sensor cleaned.

It is located near the bottom right of the driver's foot well plate, behind this vent:



You'll need to remove the plastic panel (and maybe the metal panel) to access the sensor behind it, it looks like a little black box with a thermistor inside:



Skip to 1:26 in this video to see how the panel comes apart. The procedure is for the Solara, which is the same as the 3ES, I'm not sure if your 1996 will differ much.

 

Thank you for all the response and help on this problem with my car.